Predictive building control system with neural network based comfort prediction

ABSTRACT

A building control system includes one or more controllers configured to obtain comfort feedback provided by one or more occupants of a building in response to exposing the one or more occupants to a first set of environmental conditions of the building. The one or more controllers are also configured to generate, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable, execute a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment, and operate the building equipment to drive the environmental condition of the building toward the setpoints.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application is a continuation-in-part of U.S. patent application Ser. No. 15/953,319, filed Apr. 13, 2018, which claims the benefit of and priority to U.S. Provisional Patent Application No. 62/489,975 filed Apr. 25, 2017. This application also claims the benefit of and priority to U.S. Provisional Application No. 62/883,508 filed Aug. 6, 2019. The entire disclosures of these applications are incorporated by reference herein.

BACKGROUND

The present disclosure relates generally to a predictive building control system that uses a predictive model to optimize the cost of energy consumed by HVAC equipment. The present disclosure relates more particularly to a building control system that uses a neural network model to automatically generate constraints on the optimization of the predictive model.

SUMMARY

One implementation of the present disclosure is a building control system. The building control system includes one or more controllers configured to obtain comfort feedback provided by one or more occupants of a building under a first set of environmental conditions of the building. The one or more controllers are also configured to generate, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable, execute a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment, and operate the building equipment to drive the environmental condition of the building toward the setpoints.

In some embodiments, the comfort feedback includes setpoint adjustments provided by the one or more occupants during a first time period. The one or more occupants may be predicted to be comfortable in response to a prediction that the comfort feedback (e.g., the setpoint adjustments) will satisfy a condition during a second time period.

In some embodiments, the comfort feedback includes comfort votes provided by the one or more occupants via a mobile device during a first time period. The one or more occupants may be predicted to be comfortable in response to a prediction that the comfort votes will satisfy a condition during a second time period.

In some embodiments, the one or more controllers are configured to predict whether the one or more occupants will be comfortable at a value of the environmental condition using a neural network model trained with the comfort feedback and corresponding values of the first set of environmental conditions of the building.

In some embodiments, the one or more controllers are configured to generate the one or more thresholds using a neural network including an input neuron for a value for the environmental condition (e.g., a zone temperature value) and configured to output a predicted comfort feedback (e.g., temperature setpoint change). The one or more controllers may be configured to generate the one or more thresholds by iteratively applying a plurality of values for the environmental condition at the input neuron to obtain a plurality of predicted setpoint changes associated with the plurality of values for the environmental condition, determining, from the plurality of values and the plurality of comfort feedbacks, a maximum value for the environmental condition for which the comfort feedback satisfies a condition (e.g., for which the predicted setpoint change is zero) and a minimum value for which the comfort feedback satisfies the condition, and assigning the maximum value and the minimum value as the one or more thresholds.

In some embodiments, the one or more thresholds include one or more time-varying values for a plurality of time steps in an optimization period.

Another implementation of the present disclosure is a method. The method includes obtaining comfort feedback from one or more occupants of a building while the one or more occupants are exposed to a first set of environmental conditions of the building, generating, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable, executing a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment, and operating the building equipment to drive the environmental condition of the building toward the setpoints.

In some embodiments, the comfort feedback includes setpoint adjustments provided by the one or more occupants during a first time period. The one or more occupants are predicted to be comfortable in response to a prediction that the setpoint adjustments will satisfy a condition during a second time period.

In some embodiments, the comfort feedback includes comfort votes provided by the one or more occupants via a mobile device during a first time period. The one or more occupants are predicted to be comfortable in response to a prediction that the comfort votes will satisfy a condition during a second time period.

In some embodiments, the method includes predicting whether the one or more occupants will be comfortable at a value of the environmental condition using a neural network model trained with the comfort feedback and corresponding values of the first set of environmental conditions of the building. Generating the one or more thresholds includes using a neural network including an input neuron for a value for the environmental condition and configured to output a predicted setpoint change.

In some embodiments, generating the one or more thresholds includes iteratively applying a plurality of values for the environmental condition at the input neuron to obtain a plurality of predicted setpoint changes associated with the plurality of values for the environmental condition, determining, from the plurality of values for the environmental condition and the plurality of predicted setpoint changes, a maximum value for the environmental condition for which the predicted setpoint change is zero and a minimum value for the environmental condition for which the predicted setpoint change is zero, and assigning the maximum value and the minimum value as the one or more thresholds.

In some embodiments, the one or more thresholds include one or more time-varying values for a plurality of time steps in an optimization period.

Another implementation of the present disclosure is non-transitory computer-readable media storing program instructions that, when executed by one or more processors, cause the one or more processors to perform particular operations. The operations include obtaining comfort feedback provided by one or more occupants of a building while the one or more occupants are exposed to a first set of environmental conditions of the building, generating, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable, executing a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment, and operating the building equipment to drive the environmental condition of the building toward the setpoints.

In some embodiments, the comfort feedback includes setpoint adjustments provided by the one or more occupants during a first time period, and the one or more occupants are predicted to be comfortable in response to a prediction that the setpoint adjustments will satisfy a condition during a second time period.

In some embodiments, the comfort feedback includes comfort votes provided by the one or more occupants via a mobile device during a first time period. The one or more occupants may be predicted to be comfortable in response to a prediction that the comfort votes will satisfy a condition during a second time period.

In some embodiments, the operations include predicting whether the one or more occupants will be comfortable at a value of the environmental condition using a neural network model trained with the comfort feedback and corresponding values of the first set of environmental conditions of the building. In some embodiments, the neural network model is updated over time based on additional feedback.

In some embodiments, generating the one or more thresholds includes using a neural network including an input neuron for a value for the environmental condition and configured to output a predicted setpoint change. Generating the one or more thresholds may include iteratively applying a plurality of values for the environmental condition at the input neuron to obtain a plurality of setpoint changes associated with the plurality of values for the environmental condition, determining, from the plurality of values for the environmental condition and the plurality of predicted setpoint changes, a maximum zone value for the environmental condition for which the predicted setpoint change is zero and a minimum value for the environmental condition for which the predicted setpoint change is zero, and assigning the maximum value and the minimum value as the one or more thresholds. In some embodiments, the values for the environmental condition are zone temperature values and the predicting setpoint changes are predicted temperature setpoint changes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing of a building equipped with a HVAC system, according to some embodiments.

FIG. 2 is a schematic of a waterside system (e.g., a central plant) which can be used to provide heating or cooling to the building of FIG. 1, according to some embodiments.

FIG. 3 is a block diagram of an airside system which can be used to provide heating or cooling to the building of FIG. 1, according to some embodiments.

FIG. 4 is a block diagram of a building energy system with a predictive controller, according to some embodiments.

FIG. 5 is a drawing illustrating several components of the building energy system of FIG. 4, according to some embodiments.

FIG. 6 is a block diagram illustrating the predictive controller of FIG. 4 in greater detail, according to some embodiments.

FIG. 7 is a block diagram illustrating a constraint generator of the predictive controller of FIG. 4 in greater detail, according to some embodiments.

FIG. 8 is a drawing of a convolutional neural network (CNN) model which can be generated and used by the constraint generator of FIG. 7, according to some embodiments.

FIG. 9 is a graph illustrating fixed minimum and maximum comfort bounds that a zone may operate based on under a current MPC algorithm, according to some embodiments.

FIG. 10 is a graph illustrating benefits of integrating AI with MPC on the minimum and maximum comfort bounds of FIG. 9, according to some embodiments.

FIG. 11 is a comfort controller for generating comfort constraints for use in MPC, according to some embodiments.

FIG. 12 is an illustration of a first neural network model for predicting changes in setpoints, according to some embodiments.

FIG. 13 is an illustration of a second neural network model for predicting changes in setpoints, according to some embodiments.

FIG. 14 is a graph illustrating sweeping of a zone temperature to determine comfort constraints, according to some embodiments.

FIG. 15 is a process for determining hourly comfort constraints, according to some embodiments.

FIG. 16 is a flowchart of a process for training a neural network, according to some embodiments.

FIG. 17 is a flowchart of a process for controlling building equipment to achieve predicted comfort for occupants, according to some embodiments.

DETAILED DESCRIPTION Building and HVAC System

Referring now to FIGS. 1-3, a building and HVAC system in which the systems and methods of the present disclosure can be implemented are shown, according to some embodiments. In brief overview, FIG. 1 shows a building 10 equipped with a HVAC system 100. FIG. 2 is a block diagram of a waterside system 200 which can be used to serve building 10. FIG. 3 is a block diagram of an airside system 300 which can be used to serve building 10.

Building and HVAC System

Referring particularly to FIG. 1, a perspective view of a building 10 is shown. Building 10 is served by a BMS. A BMS is, in general, a system of devices configured to control, monitor, and manage equipment in or around a building or building area. A BMS can include, for example, a HVAC system, a security system, a lighting system, a fire alerting system, any other system that is capable of managing building functions or devices, or any combination thereof.

The BMS that serves building 10 includes a HVAC system 100. HVAC system 100 can include a plurality of HVAC devices (e.g., heaters, chillers, air handling units, pumps, fans, thermal energy storage, etc.) configured to provide heating, cooling, ventilation, or other services for building 10. For example, HVAC system 100 is shown to include a waterside system 120 and an airside system 130. Waterside system 120 may provide a heated or chilled fluid to an air handling unit of airside system 130. Airside system 130 may use the heated or chilled fluid to heat or cool an airflow provided to building 10. An exemplary waterside system and airside system which can be used in HVAC system 100 are described in greater detail with reference to FIGS. 2-3.

HVAC system 100 is shown to include a chiller 102, a boiler 104, and a rooftop air handling unit (AHU) 106. Waterside system 120 may use boiler 104 and chiller 102 to heat or cool a working fluid (e.g., water, glycol, etc.) and may circulate the working fluid to AHU 106. In various embodiments, the HVAC devices of waterside system 120 can be located in or around building 10 (as shown in FIG. 1) or at an offsite location such as a central plant (e.g., a chiller plant, a steam plant, a heat plant, etc.). The working fluid can be heated in boiler 104 or cooled in chiller 102, depending on whether heating or cooling is required in building 10. Boiler 104 may add heat to the circulated fluid, for example, by burning a combustible material (e.g., natural gas) or using an electric heating element. Chiller 102 may place the circulated fluid in a heat exchange relationship with another fluid (e.g., a refrigerant) in a heat exchanger (e.g., an evaporator) to absorb heat from the circulated fluid. The working fluid from chiller 102 and/or boiler 104 can be transported to AHU 106 via piping 108.

AHU 106 may place the working fluid in a heat exchange relationship with an airflow passing through AHU 106 (e.g., via one or more stages of cooling coils and/or heating coils). The airflow can be, for example, outside air, return air from within building 10, or a combination of both. AHU 106 may transfer heat between the airflow and the working fluid to provide heating or cooling for the airflow. For example, AHU 106 can include one or more fans or blowers configured to pass the airflow over or through a heat exchanger containing the working fluid. The working fluid may then return to chiller 102 or boiler 104 via piping 110.

Airside system 130 may deliver the airflow supplied by AHU 106 (i.e., the supply airflow) to building 10 via air supply ducts 112 and may provide return air from building 10 to AHU 106 via air return ducts 114. In some embodiments, airside system 130 includes multiple variable air volume (VAV) units 116. For example, airside system 130 is shown to include a separate VAV unit 116 on each floor or zone of building 10. VAV units 116 can include dampers or other flow control elements that can be operated to control an amount of the supply airflow provided to individual zones of building 10. In other embodiments, airside system 130 delivers the supply airflow into one or more zones of building 10 (e.g., via supply ducts 112) without using intermediate VAV units 116 or other flow control elements. AHU 106 can include various sensors (e.g., temperature sensors, pressure sensors, etc.) configured to measure attributes of the supply airflow. AHU 106 may receive input from sensors located within AHU 106 and/or within the building zone and may adjust the flow rate, temperature, or other attributes of the supply airflow through AHU 106 to achieve setpoint conditions for the building zone.

Waterside System

Referring now to FIG. 2, a block diagram of a waterside system 200 is shown, according to some embodiments. In various embodiments, waterside system 200 may supplement or replace waterside system 120 in HVAC system 100 or can be implemented separate from HVAC system 100. When implemented in HVAC system 100, waterside system 200 can include a subset of the HVAC devices in HVAC system 100 (e.g., boiler 104, chiller 102, pumps, valves, etc.) and may operate to supply a heated or chilled fluid to AHU 106. The HVAC devices of waterside system 200 can be located within building 10 (e.g., as components of waterside system 120) or at an offsite location such as a central plant.

In FIG. 2, waterside system 200 is shown as a central plant having a plurality of subplants 202-212. Subplants 202-212 are shown to include a heater subplant 202, a heat recovery chiller subplant 204, a chiller subplant 206, a cooling tower subplant 208, a hot thermal energy storage (TES) subplant 210, and a cold thermal energy storage (TES) subplant 212. Subplants 202-212 consume resources (e.g., water, natural gas, electricity, etc.) from utilities to serve thermal energy loads (e.g., hot water, cold water, heating, cooling, etc.) of a building or campus. For example, heater subplant 202 can be configured to heat water in a hot water loop 214 that circulates the hot water between heater subplant 202 and building 10. Chiller subplant 206 can be configured to chill water in a cold water loop 216 that circulates the cold water between chiller subplant 206 building 10. Heat recovery chiller subplant 204 can be configured to transfer heat from cold water loop 216 to hot water loop 214 to provide additional heating for the hot water and additional cooling for the cold water. Condenser water loop 218 may absorb heat from the cold water in chiller subplant 206 and reject the absorbed heat in cooling tower subplant 208 or transfer the absorbed heat to hot water loop 214. Hot TES subplant 210 and cold TES subplant 212 may store hot and cold thermal energy, respectively, for subsequent use.

Hot water loop 214 and cold water loop 216 may deliver the heated and/or chilled water to air handlers located on the rooftop of building 10 (e.g., AHU 106) or to individual floors or zones of building 10 (e.g., VAV units 116). The air handlers push air past heat exchangers (e.g., heating coils or cooling coils) through which the water flows to provide heating or cooling for the air. The heated or cooled air can be delivered to individual zones of building 10 to serve thermal energy loads of building 10. The water then returns to subplants 202-212 to receive further heating or cooling.

Although subplants 202-212 are shown and described as heating and cooling water for circulation to a building, it is understood that any other type of working fluid (e.g., glycol, CO2, etc.) can be used in place of or in addition to water to serve thermal energy loads. In other embodiments, subplants 202-212 may provide heating and/or cooling directly to the building or campus without requiring an intermediate heat transfer fluid. These and other variations to waterside system 200 are within the teachings of the present disclosure.

Each of subplants 202-212 can include a variety of equipment configured to facilitate the functions of the subplant. For example, heater subplant 202 is shown to include a plurality of heating elements 220 (e.g., boilers, electric heaters, etc.) configured to add heat to the hot water in hot water loop 214. Heater subplant 202 is also shown to include several pumps 222 and 224 configured to circulate the hot water in hot water loop 214 and to control the flow rate of the hot water through individual heating elements 220. Chiller subplant 206 is shown to include a plurality of chillers 232 configured to remove heat from the cold water in cold water loop 216. Chiller subplant 206 is also shown to include several pumps 234 and 236 configured to circulate the cold water in cold water loop 216 and to control the flow rate of the cold water through individual chillers 232.

Heat recovery chiller subplant 204 is shown to include a plurality of heat recovery heat exchangers 226 (e.g., refrigeration circuits) configured to transfer heat from cold water loop 216 to hot water loop 214. Heat recovery chiller subplant 204 is also shown to include several pumps 228 and 230 configured to circulate the hot water and/or cold water through heat recovery heat exchangers 226 and to control the flow rate of the water through individual heat recovery heat exchangers 226. Cooling tower subplant 208 is shown to include a plurality of cooling towers 238 configured to remove heat from the condenser water in condenser water loop 218. Cooling tower subplant 208 is also shown to include several pumps 240 configured to circulate the condenser water in condenser water loop 218 and to control the flow rate of the condenser water through individual cooling towers 238.

Hot TES subplant 210 is shown to include a hot TES tank 242 configured to store the hot water for later use. Hot TES subplant 210 may also include one or more pumps or valves configured to control the flow rate of the hot water into or out of hot TES tank 242. Cold TES subplant 212 is shown to include cold TES tanks 244 configured to store the cold water for later use. Cold TES subplant 212 may also include one or more pumps or valves configured to control the flow rate of the cold water into or out of cold TES tanks 244.

In some embodiments, one or more of the pumps in waterside system 200 (e.g., pumps 222, 224, 228, 230, 234, 236, and/or 240) or pipelines in waterside system 200 include an isolation valve associated therewith. Isolation valves can be integrated with the pumps or positioned upstream or downstream of the pumps to control the fluid flows in waterside system 200. In various embodiments, waterside system 200 can include more, fewer, or different types of devices and/or subplants based on the particular configuration of waterside system 200 and the types of loads served by waterside system 200.

Airside System

Referring now to FIG. 3, a block diagram of an airside system 300 is shown, according to some embodiments. In various embodiments, airside system 300 may supplement or replace airside system 130 in HVAC system 100 or can be implemented separate from HVAC system 100. When implemented in HVAC system 100, airside system 300 can include a subset of the HVAC devices in HVAC system 100 (e.g., AHU 106, VAV units 116, ducts 112-114, fans, dampers, etc.) and can be located in or around building 10. Airside system 300 may operate to heat or cool an airflow provided to building 10 using a heated or chilled fluid provided by waterside system 200.

In FIG. 3, airside system 300 is shown to include an economizer-type air handling unit (AHU) 302. Economizer-type AHUs vary the amount of outside air and return air used by the air handling unit for heating or cooling. For example, AHU 302 may receive return air 304 from building zone 306 via return air duct 308 and may deliver supply air 310 to building zone 306 via supply air duct 312. In some embodiments, AHU 302 is a rooftop unit located on the roof of building 10 (e.g., AHU 106 as shown in FIG. 1) or otherwise positioned to receive both return air 304 and outside air 314. AHU 302 can be configured to operate exhaust air damper 316, mixing damper 318, and outside air damper 320 to control an amount of outside air 314 and return air 304 that combine to form supply air 310. Any return air 304 that does not pass through mixing damper 318 can be exhausted from AHU 302 through exhaust damper 316 as exhaust air 322.

Each of dampers 316-320 can be operated by an actuator. For example, exhaust air damper 316 can be operated by actuator 324, mixing damper 318 can be operated by actuator 326, and outside air damper 320 can be operated by actuator 328. Actuators 324-328 may communicate with an AHU controller 330 via a communications link 332. Actuators 324-328 may receive control signals from AHU controller 330 and may provide feedback signals to AHU controller 330. Feedback signals can include, for example, an indication of a current actuator or damper position, an amount of torque or force exerted by the actuator, diagnostic information (e.g., results of diagnostic tests performed by actuators 324-328), status information, commissioning information, configuration settings, calibration data, and/or other types of information or data that can be collected, stored, or used by actuators 324-328. AHU controller 330 can be an economizer controller configured to use one or more control algorithms (e.g., state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, feedback control algorithms, etc.) to control actuators 324-328.

Still referring to FIG. 3, AHU 302 is shown to include a cooling coil 334, a heating coil 336, and a fan 338 positioned within supply air duct 312. Fan 338 can be configured to force supply air 310 through cooling coil 334 and/or heating coil 336 and provide supply air 310 to building zone 306. AHU controller 330 may communicate with fan 338 via communications link 340 to control a flow rate of supply air 310. In some embodiments, AHU controller 330 controls an amount of heating or cooling applied to supply air 310 by modulating a speed of fan 338.

Cooling coil 334 may receive a chilled fluid from waterside system 200 (e.g., from cold water loop 216) via piping 342 and may return the chilled fluid to waterside system 200 via piping 344. Valve 346 can be positioned along piping 342 or piping 344 to control a flow rate of the chilled fluid through cooling coil 334. In some embodiments, cooling coil 334 includes multiple stages of cooling coils that can be independently activated and deactivated (e.g., by AHU controller 330, by BMS controller 366, etc.) to modulate an amount of cooling applied to supply air 310.

Heating coil 336 may receive a heated fluid from waterside system 200 (e.g., from hot water loop 214) via piping 348 and may return the heated fluid to waterside system 200 via piping 350. Valve 352 can be positioned along piping 348 or piping 350 to control a flow rate of the heated fluid through heating coil 336. In some embodiments, heating coil 336 includes multiple stages of heating coils that can be independently activated and deactivated (e.g., by AHU controller 330, by BMS controller 366, etc.) to modulate an amount of heating applied to supply air 310.

Each of valves 346 and 352 can be controlled by an actuator. For example, valve 346 can be controlled by actuator 354 and valve 352 can be controlled by actuator 356. Actuators 354-356 may communicate with AHU controller 330 via communications links 358-360. Actuators 354-356 may receive control signals from AHU controller 330 and may provide feedback signals to controller 330. In some embodiments, AHU controller 330 receives a measurement of the supply air temperature from a temperature sensor 362 positioned in supply air duct 312 (e.g., downstream of cooling coil 334 and/or heating coil 336). AHU controller 330 may also receive a measurement of the temperature of building zone 306 from a temperature sensor 364 located in building zone 306.

In some embodiments, AHU controller 330 operates valves 346 and 352 via actuators 354-356 to modulate an amount of heating or cooling provided to supply air 310 (e.g., to achieve a setpoint temperature for supply air 310 or to maintain the temperature of supply air 310 within a setpoint temperature range). The positions of valves 346 and 352 affect the amount of heating or cooling provided to supply air 310 by cooling coil 334 or heating coil 336 and may correlate with the amount of energy consumed to achieve a desired supply air temperature. AHU 330 may control the temperature of supply air 310 and/or building zone 306 by activating or deactivating coils 334-336, adjusting a speed of fan 338, or a combination of both.

Still referring to FIG. 3, airside system 300 is shown to include a building management system (BMS) controller 366 and a client device 368. BMS controller 366 can include one or more computer systems (e.g., servers, supervisory controllers, subsystem controllers, etc.) that serve as system level controllers, application or data servers, head nodes, or master controllers for airside system 300, waterside system 200, HVAC system 100, and/or other controllable systems that serve building 10. BMS controller 366 may communicate with multiple downstream building systems or subsystems (e.g., HVAC system 100, a security system, a lighting system, waterside system 200, etc.) via a communications link 370 according to like or disparate protocols (e.g., LON, BACnet, etc.). In various embodiments, AHU controller 330 and BMS controller 366 can be separate (as shown in FIG. 3) or integrated. In an integrated implementation, AHU controller 330 can be a software module configured for execution by a processor of BMS controller 366.

In some embodiments, AHU controller 330 receives information from BMS controller 366 (e.g., commands, setpoints, operating boundaries, etc.) and provides information to BMS controller 366 (e.g., temperature measurements, valve or actuator positions, operating statuses, diagnostics, etc.). For example, AHU controller 330 may provide BMS controller 366 with temperature measurements from temperature sensors 362-364, equipment on/off states, equipment operating capacities, and/or any other information that can be used by BMS controller 366 to monitor or control a variable state or condition within building zone 306.

Client device 368 can include one or more human-machine interfaces or client interfaces (e.g., graphical user interfaces, reporting interfaces, text-based computer interfaces, client-facing web services, web servers that provide pages to web clients, etc.) for controlling, viewing, or otherwise interacting with HVAC system 100, its subsystems, and/or devices. Client device 368 can be a computer workstation, a client terminal, a remote or local interface, or any other type of user interface device. Client device 368 can be a stationary terminal or a mobile device. For example, client device 368 can be a desktop computer, a computer server with a user interface, a laptop computer, a tablet, a smartphone, a PDA, or any other type of mobile or non-mobile device. Client device 368 may communicate with BMS controller 366 and/or AHU controller 330 via communications link 372.

Building Energy System with Predictive Control

Referring now to FIGS. 4-5, a building energy system 400 with predictive control is shown, according to some embodiments. Several of the components shown in system 400 may be part of HVAC system 100, waterside system 200, and/or airside system 300, as described with reference to FIGS. 1-3. For example, system 400 is shown to include a campus 402 including one or more buildings 404 and a central plant 406. Buildings 404 may include any of a variety of building equipment (e.g., HVAC equipment) configured to serve buildings 404. For example, buildings 404 may include one or more air handling units, rooftop units, chillers, boilers, variable refrigerant flow (VRF) systems, or other HVAC equipment operable to provide heating or cooling to buildings 404. Central plant 406 may include some or all of the components of waterside system 200 (e.g., a heater subplant 202, a heat recovery chiller subplant 204, a chiller subplant 206, a cooling tower subplant 208, a hot thermal energy storage (TES) subplant 210, and a cold thermal energy storage (TES) subplant 212, etc.). The equipment of central plant 406 (e.g., waterside equipment) can be used in combination with the equipment of buildings 404 (e.g., airside equipment) to provide heating or cooling to buildings 404.

Campus 402 can be powered by several different power sources including an energy grid 412, a battery 414, and green energy generation 408. Energy grid 412 may include an electric grid operated by an electric utility. The power provided by energy grid 412 is shown as P_(grid). Green energy generation 408 can include any system or device that generates energy using a renewable energy source (i.e., green energy). For example, green energy generation 408 may include a photovoltaic field, a wind turbine array, a hydroelectric generator, a geothermal generator, or any other type of equipment or system that collects and/or generates green energy for use in system 400. The power provided by green energy generation 408 is shown as P_(green). Battery 414 can be configured to store and discharge electric energy (i.e., electricity provided by energy grid 412 and/or green energy generation 408. The power provided by battery 414 is shown as P_(bat), which can be positive if battery 414 is discharging or negative if battery 414 is charging.

Battery power inverter 416 may be configured to convert electric power between direct current (DC) and alternating current (AC). For example, battery 414 may be configured to store and output DC power, whereas energy grid 412 and campus 402 may be configured to consume and provide AC power. Battery power inverter 416 may be used to convert DC power from battery 414 into a sinusoidal AC output synchronized to the grid frequency of energy grid 412 and/or campus 402. Battery power inverter 416 may also be used to convert AC power from energy grid 412 into DC power that can be stored in battery 414. The power output of battery 414 is shown as P_(bat). P_(bat) may be positive if battery 414 is providing power to power inverter 416 (i.e., battery 414 is discharging) or negative if battery 414 is receiving power from power inverter 416 (i.e., battery 414 is charging).

Green power inverter 418 may also be configured to convert electric power between direct current (DC) and alternating current (AC). For example, green energy generation 408 may be configured to generate DC power, whereas campus 402 may be configured to consume AC power. Green power inverter 418 may be used to convert DC power from green energy generation 408 into a sinusoidal AC output synchronized to the grid frequency of energy grid 412 and/or campus 402.

In some instances, power inverters 416-418 receives a DC power output from battery 414 and/or green energy generation 408 and converts the DC power output to an AC power output that can be provided to campus 402. Power inverters 416-418 may synchronize the frequency of the AC power output with that of energy grid 412 (e.g., 50 Hz or 60 Hz) using a local oscillator and may limit the voltage of the AC power output to no higher than the grid voltage. In some embodiments, power inverters 416-418 are resonant inverters that include or use LC circuits to remove the harmonics from a simple square wave in order to achieve a sine wave matching the frequency of energy grid 412. In various embodiments, power inverters 416-418 may operate using high-frequency transformers, low-frequency transformers, or without transformers. Low-frequency transformers may convert the DC output from battery 414 or green energy generation 408 directly to the AC output provided to campus 402. High-frequency transformers may employ a multi-step process that involves converting the DC output to high-frequency AC, then back to DC, and then finally to the AC output provided to campus 402.

Point of interconnection (POI) 410 is the point at which campus 402, energy grid 412, and power inverters 416-418 are electrically connected. The power supplied to POI 410 from battery power inverter 416 is shown as P_(bat). P_(bat) may be positive if battery power inverter 416 is providing power to POI 410 (i.e., battery 414 is discharging) or negative if battery power inverter 416 is receiving power from POI 410 (i.e., battery 414 is charging). The power supplied to POI 410 from energy grid 412 is shown as P_(grid), and the power supplied to POI 410 from green power inverter 418 is shown as P_(green). P_(bat), P_(green), and P_(grid) combine at POI 410 to form P_(campus) (i.e., P_(campus)=P_(grid)+P_(bat)+P_(green)). P_(campus) may be defined as the power provided to campus 402 from POI 410. In some instances, P_(campus) is greater than P_(grid). For example, when battery 414 is discharging, P_(bat) may be positive which adds to the grid power P_(grid) when P_(bat) and P_(grid) combine at POI 410. Similarly, when green energy generation 408 is providing power to POI 410, P_(green) may be positive which adds to the grid power P_(grid) when P_(green) and P_(grid) combine at POI 410. In other instances, P_(campus) may be less than P_(grid). For example, when battery 414 is charging, P_(bat) may be negative which subtracts from the grid power P_(grid) when P_(bat) and P_(grid) combine at POI 410.

Predictive controller 420 can be configured to control the equipment of campus 402 and battery power inverter 416 to optimize the economic cost of heating or cooling buildings 404. In some embodiments, predictive controller 420 generates and provides a battery power setpoint P_(sp,bat) to battery power inverter 416. The battery power setpoint P_(sp,bat) may include a positive or negative power value (e.g., kW) which causes battery power inverter 416 to charge battery 414 (when P_(sp,bat) is negative) using power available at POI 410 or discharge battery 414 (when P_(sp,bat) is positive) to provide power to POI 410 in order to achieve the battery power setpoint P_(sp,bat).

In some embodiments, predictive controller 420 generates and provides control signals to campus 402. Predictive controller 420 may use a multi-stage optimization technique to generate the control signals. For example, predictive controller 420 may include an economic controller configured to determine the optimal amount of power to be consumed by campus 402 at each time step during the optimization period. The optimal amount of power to be consumed may minimize a cost function that accounts for the cost of energy consumed by the equipment of buildings 404 and/or central plant 406. The cost of energy may be based on time-varying energy prices defining the cost of purchasing electricity from energy grid 412 at various times. In some embodiments, predictive controller 420 determines an optimal amount of power to purchase from energy grid 412 (i.e., a grid power setpoint P_(sp,grid)) and an optimal amount of power to store or discharge from battery 414 (i.e., a battery power setpoint P_(sp,bat)) at each of the plurality of time steps. In some embodiments, predictive controller 420 determines an optimal power setpoint for each subsystem or device of campus 402 (e.g., each subplant of central plant 406, each device of building equipment, etc.). Predictive controller 420 may monitor the actual power usage of campus 402 and may utilize the actual power usage as a feedback signal when generating the optimal power setpoints.

Predictive controller 420 may include a tracking controller configured to generate temperature setpoints (e.g., a zone temperature setpoint T_(sp,zone,) a supply air temperature setpoint T_(sp,sa), etc.) that achieve the optimal amount of power consumption at each time step. In some embodiments, predictive controller 420 uses equipment models for the equipment of buildings 404 and campus 402 to determine an amount of heating or cooling that can be generated by such equipment based on the optimal amount of power consumption. Predictive controller 420 can use a zone temperature model in combination with weather forecasts from a weather service to predict how the temperature of the building zone T_(zone) will change based on the power setpoints and/or the temperature setpoints.

In some embodiments, predictive controller 420 uses the temperature setpoints to generate the control signals for the equipment of buildings 404 and campus 402. The control signals may include on/off commands, speed setpoints for fans, position setpoints for actuators and valves, or other operating commands for individual devices of campus 402. In other embodiments, the control signals may include the temperature setpoints (e.g., a zone temperature setpoint T_(sp,zone), a supply air temperature setpoint T_(sp,sa), etc.) generated by predictive controller 420. The temperature setpoints can be provided to campus 402 or local controllers for campus 402 which operate to achieve the temperature setpoints. For example, a local controller for an AHU fan within buildings 404 may receive a measurement of the supply air temperature T_(sa) from a supply air temperature sensor and/or a measurement the zone temperature T_(zone) from a zone temperature sensor. The local controller can use a feedback control process (e.g., PID, ESC, MPC, etc.) to adjust the speed of the AHU fan to drive the measured temperature(s) to the temperature setpoint(s). Similar feedback control processes can be used to control the positions of actuators and valves. The multi-stage optimization performed by predictive controller 420 is described in greater detail with reference to FIG. 6.

Predictive Controller

Referring now to FIG. 6, a block diagram illustrating predictive controller 420 in greater detail is shown, according to an exemplary embodiment. Predictive controller 420 is shown to include a communications interface 602 and a processing circuit 604. Communications interface 602 may facilitate communications between predictive controller 420 and external systems or devices. For example, communications interface 602 may receive measurements of the zone temperature T_(zone) from a zone temperature sensor 622 and measurements of the power usage of campus 402. In some embodiments, communications interface 602 receives measurements of the state-of-charge (SOC) of battery 414, which can be provided as a percentage of the maximum battery capacity (i.e., battery %). Similarly, communications interface 602 may receive an indication of the amount of power being generated by green energy generation 408, which can be provided as a percentage of the maximum green power generation (i.e., green %). Communications interface 602 can receive weather forecasts from a weather service 618 and predicted energy costs and demand costs from an electric utility 616. In some embodiments, predictive controller 420 uses communications interface 602 to provide control signals campus 402 and battery power inverter 416.

Communications interface 602 may include wired or wireless communications interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.) for conducting data communications external systems or devices. In various embodiments, the communications may be direct (e.g., local wired or wireless communications) or via a communications network (e.g., a WAN, the Internet, a cellular network, etc.). For example, communications interface 602 can include an Ethernet card and port for sending and receiving data via an Ethernet-based communications link or network. In another example, communications interface 602 can include a WiFi transceiver for communicating via a wireless communications network or cellular or mobile phone communications transceivers.

Processing circuit 604 is shown to include a processor 606 and memory 608. Processor 606 may be a general purpose or specific purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable processing components. Processor 606 is configured to execute computer code or instructions stored in memory 608 or received from other computer readable media (e.g., CDROM, network storage, a remote server, etc.).

Memory 608 may include one or more devices (e.g., memory units, memory devices, storage devices, etc.) for storing data and/or computer code for completing and/or facilitating the various processes described in the present disclosure. Memory 608 may include random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and/or computer instructions. Memory 608 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. Memory 608 may be communicably connected to processor 606 via processing circuit 604 and may include computer code for executing (e.g., by processor 606) one or more processes described herein. When processor 606 executes instructions stored in memory 608 for completing the various activities described herein, processor 606 generally configures predictive controller 420 (and more particularly processing circuit 604) to complete such activities.

Still referring to FIG. 6, predictive controller 420 is shown to include an economic controller 610, a tracking controller 612, and an equipment controller 614. Controllers 610-614 can be configured to perform a multi-state optimization process to generate control signals for power battery power inverter 416 and campus 402. In brief overview, economic controller 610 can optimize a predictive cost function to determine an optimal amount of power to purchase from energy grid 412 (i.e., a grid power setpoint P_(sp,grid)), an optimal amount of power to store or discharge from battery 414 (i.e., a battery power setpoint P_(sp,bat)), and/or an optimal amount of power to be consumed by campus 402 (i.e., a campus power setpoint P_(sp,campus)) at each time step of an optimization period. Tracking controller 612 can use the optimal power setpoints P_(sp,grid), P_(sp,bat), and/or P_(sp,campus) to determine optimal temperature setpoints (e.g., a zone temperature setpoint T_(sp,zone,) a supply air temperature setpoint T_(sp,sa), etc.) and an optimal battery charge or discharge rate (i.e., Bat_(C/D)). Equipment controller 614 can use the optimal temperature setpoints T_(sp,zone) or T_(sp,sa) to generate control signals for campus 402 that drive the actual (e.g., measured) temperatures T_(zone) and/or T_(sa) to the setpoints (e.g., using a feedback control technique). Each of controllers 610-614 is described in detail below.

Economic Controller

Economic controller 610 can be configured to optimize a predictive cost function to determine an optimal amount of power to purchase from energy grid 412 (i.e., a grid power setpoint P_(sp,grid)), an optimal amount of power to store or discharge from battery 414 (i.e., a battery power setpoint P_(sp,bat)), and/or an optimal amount of power to be consumed by campus 402 (i.e., a campus power setpoint P_(sp,campus)) at each time step of an optimization period. An example of a predictive cost function which can be optimized by economic controller 610 is shown in the following equation:

${\min (J)} = {{\sum\limits_{k = 1}^{h}{{C_{ec}(k)}{P_{CPO}(k)}\Delta \; t}} + {\sum\limits_{k = 1}^{h}{{C_{ec}(k)}{P_{RTU}(k)}\Delta \; t}} + {\sum\limits_{k = 1}^{h}{{C_{ec}(k)}{P_{VRF}(k)}\Delta \; t}} + {\sum\limits_{k = 1}^{h}{{C_{ec}(k)}{P_{AHU}(k)}\Delta \; t}} + {C_{DC}{\max\limits_{k}\left( {P_{grid}(k)} \right)}} - {\sum\limits_{k = 1}^{h}{{C_{ec}(k)}{p_{bat}(k)}\Delta \; t}}}$

where C_(ec)(k) is the cost per unit of electricity (e.g., $/kWh) purchased from energy grid 412 during time step k, P_(CPO)(k) is the total power consumption (e.g., kW) of central plant 406 time step k, P_(RTU)(k) is the total power consumption of the RTUs of buildings 404 during time step k, P_(VRF)(k) is the total power consumption of the VRF system used to serve buildings 404 during time step k, P_(AHU)(k) is the total power consumption of the AHUs of buildings 404 during time step k, C_(DC) is the demand charge rate (e.g., $/kW), the max( ) term selects the maximum value of P_(grid) (k) during any time step k of the optimization period, P_(bat)(k) is the amount of power discharged from battery 414 during time step k, and Δt is the duration of each time step k. Economic controller 610 can optimize the predictive cost function J over the duration of the optimization period (e.g., from time step k=1 to time step k=h) to predict the total cost of heating or cooling campus 402 over the duration of the optimization period.

The first term of the predictive cost function J represents the cost of electricity consumed by central plant 406 over the duration of the optimization period. The values of the parameter C_(ec)(k) at each time step k can be defined by the energy cost information provided by electric utility 616. In some embodiments, the cost of electricity varies as a function of time, which results in different values of C_(ec)(k) at different time steps k. The variable P_(CPO)(k) is a decision variable which can be optimized by economic controller 610. In some embodiments, P_(CPO)(k) is a component of P_(campus) (e.g., P_(campus)=P_(CPO) P_(RTU) P_(VRF) P_(AHU)). In some embodiments, P_(CPO)(k) is a summation of the power consumptions of each subplant of central plant 406 (e.g., P_(CPO)=P_(ChillerSubplant) P_(HRCSubplant) P_(HeaterSubplant)).

In some embodiments, economic controller 610 uses one or more subplant curves for central plant 406 to relate the value of P_(CPO) to the production of central plant 406 (e.g., hot water production, chilled water production, etc.). For example, if a chiller subplant 206 is used to generate a chilled fluid, a subplant curve for chiller subplant 206 can be used to model the performance of chiller subplant 206. In some embodiments, the subplant curve defines the relationship between input resources and output resources of chiller subplant 206. For example, the subplant curve for chiller subplant 206 may define the electricity consumption (e.g., kW) of chiller subplant 206 as a function of the amount of cooling provided by chiller subplant 206 (e.g., tons). Economic controller 610 can use the subplant curve for chiller subplant 206 to determine an amount of electricity consumption (kW) that corresponds to a given amount of cooling (tons). Similar subplant curves can be used to model the performance of other subplants of central plant 406. Several examples of subplant curves which can be used by economic controller 610 are described in greater detail in U.S. patent application Ser. No. 14/634,609 filed Feb. 27, 2015, the entire disclosure of which is incorporated by reference herein.

The second, third, and fourth terms of the predictive cost function J represent the cost of electricity consumed by the equipment of buildings 404. For example, the second term of the predictive cost function J represents the cost of electricity consumed by one or more AHUs of buildings 404. The third term of the predictive cost function J represents the cost of electricity consumed by a VRF system of buildings 404. The fourth term of the predictive cost function J represents the cost of electricity consumed by one or more RTUs of buildings 404. In some embodiments, economic controller 610 uses equipment performance curves to model the power consumptions P_(RTU), P_(VRF), and P_(AHU) as a function of the amount of heating or cooling provided by the respective equipment of buildings 404. The equipment performance curves may be similar to the subplant curves in that they define a relationship between the heating or cooling load on a system or device and the power consumption of that system or device. The subplant curves and equipment performance curves can be used by economic controller 610 to impose constraints on the predictive cost function J.

The fifth term of the predictive cost function J represents the demand charge. Demand charge is an additional charge imposed by some utility providers based on the maximum power consumption during an applicable demand charge period. For example, the demand charge rate C_(DC) may be specified in terms of dollars per unit of power (e.g., $/kW) and may be multiplied by the peak power usage (e.g., kW) during a demand charge period to calculate the demand charge. In the predictive cost function J, the demand charge rate C_(DC) may be defined by the demand cost information received from electric utility 616. The variable P_(grid)(k) is a decision variable which can be optimized by economic controller 610 in order to reduce the peak power usage max(P_(grid)(k)) that occurs during the demand charge period. Load shifting may allow economic controller 610 to smooth momentary spikes in the electric demand of campus 402 by storing energy in battery 414 when the power consumption of campus 402 is low. The stored energy can be discharged from battery 414 when the power consumption of campus 402 is high in order to reduce the peak power draw P_(grid) from energy grid 412, thereby decreasing the demand charge incurred.

The final term of the predictive cost function J represents the cost savings resulting from the use of battery 414. Unlike the previous terms in the cost function J, the final term subtracts from the total cost. The values of the parameter C_(ec)(k) at each time step k can be defined by the energy cost information provided by electric utility 616. In some embodiments, the cost of electricity varies as a function of time, which results in different values of C_(ec)(k) at different time steps k. The variable P_(bat)(k) is a decision variable which can be optimized by economic controller 610. A positive value of P_(bat)(k) indicates that battery 414 is discharging, whereas a negative value of P_(bat)(k) indicates that battery 414 is charging. The power discharged from battery 414 P_(bat)(k) can be used to satisfy some or all of the total power consumption P_(total)(k) of campus 402, which reduces the amount of power P_(grid)(k) purchased from energy grid 412 (i.e., P_(grid)(k)=P_(total)(k)−P_(bat)(k)−P_(green)(k)). However, charging battery 414 results in a negative value of P_(bat)(k) which adds to the total amount of power P_(grid)(k) purchased from energy grid 412.

In some embodiments, the power P_(green) provided by green energy generation 408 is not included in the predictive cost function J because generating green power does not incur a cost. However, the power P_(green) generated by green energy generation 408 can be used to satisfy some or all of the total power consumption P_(campus)(k) of campus 402, which reduces the amount of power P_(grid)(k) purchased from energy grid 412 (i.e., P_(grid)(k)=P_(campus)(k)−P_(bat)(k)−P_(green)(k)). The amount of green power P_(green) generated during any time step k can be predicted by economic controller 610. Several techniques for predicting the amount of green power generated by green energy generation 408 are described in U.S. patent application Ser. No. 15/247,869, U.S. patent application Ser. No. 15/247,844, and U.S. patent application Ser. No. 15/247,788. Each of these patent applications has a filing date of Aug. 25, 2016, and the entire disclosure of each of these patent applications is incorporated by reference herein.

Economic controller 610 can optimize the predictive cost function J over the duration of the optimization period to determine optimal values of the decision variables at each time step during the optimization period. In some embodiments, the optimization period has a duration of approximately one day and each time step is approximately fifteen minutes. However, the durations of the optimization period and the time steps can vary in other embodiments and can be adjusted by a user. Advantageously, economic controller 610 can use battery 414 to perform load shifting by drawing electricity from energy grid 412 when energy prices are low and/or when the power consumed by campus 402 is low. The electricity can be stored in battery 414 and discharged later when energy prices are high and/or the power consumption of campus 402 is high. This enables economic controller 610 to reduce the cost of electricity consumed by campus 402 and can smooth momentary spikes in the electric demand of campus 402, thereby reducing the demand charge incurred.

Economic controller 610 can be configured to impose constraints on the optimization of the predictive cost function J. In some embodiments, economic controller 610 is configured to optimize the predictive cost function J subject to a set of equality constraints and inequality constraints. For example, the optimization performed by economic controller 610 can be described by the following equation:

min J(x)subject to Ax≤b, Hx=g

where x is a matrix of the decision variables in predictive cost function J (e.g., P_(CPO), P_(RTU), P_(VRF), P_(AHU), P_(grid), P_(bat), etc.), A and b are a matrix and vector (respectively) which describe inequality constraints on the optimization problem, and H and g are a matrix and vector (respectively) which describe equality constraints on the optimization problem. The inequality constraints and the equality constraints may be generated by constraint generator 620, described in greater detail below.

In some embodiments, the matrix x of decision variables has the form:

x=[P _(CPO,1 . . . h) ,P _(RTU,1 . . . h) ,P _(VRF,1 . . . h) ,P _(AHU,1 . . . h) ,P _(grid,1 . . . h) P _(bat,1 . . . h)]^(T)

where P_(CPO,1 . . . h), P_(RTU,1 . . . h), P_(VRF,1 . . . h), P_(AHU,1 . . . h), P_(grid,1 . . . h) and P_(bat,1 . . . h) are h-dimensional vectors representing the power consumption of central plant 406, one or more RTUs of buildings 404, a VRF system of buildings 404, one or more AHUs of buildings 404, the power purchased from energy grid 412, and the power stored or discharged from battery 414 at each of the h time steps of the optimization period.

Economic controller 610 can optimize the predictive cost function J subject to the constraints to determine optimal values for the decision variables P_(CPO), P_(RTU), P_(VRF), P_(AHU), P_(grid), and P_(bat), where P_(campus)=P_(bat)+P_(grid)+P_(green). In some embodiments, economic controller 610 uses the optimal values for P_(campus), P_(bat), and/or P_(grid) to generate power setpoints for tracking controller 612. The power setpoints can include battery power setpoints P_(sp,bat), grid power setpoints P_(sp,grid), central plant power setpoints P_(sp,CPO), AHU power setpoints P_(sp,AHU), VRF power setpoints P_(sp,VRF), RTU power setpoints P_(sp,RTU), and/or power setpoints for each subplant of central plant 406 for each of the time steps k in the optimization period. Economic controller 610 can provide the power setpoints to tracking controller 612.

Tracking Controller

Tracking controller 612 can use the optimal power setpoints generated by economic controller 610 (e.g., P_(sp,bat), P_(sp,grid), P_(sp,CPO), P_(sp,AHU), P_(sp,VRF), P_(sp,RTU), P_(sp,campus), etc.) to determine optimal temperature setpoints (e.g., a zone temperature setpoint T_(sp,zone), a supply air temperature setpoint T_(sp,sa), etc.) and an optimal battery charge or discharge rate (i.e., Bat_(C/D)). In some embodiments, tracking controller 612 generates a zone temperature setpoint T_(sp,zone)and/or a supply air temperature setpoint T_(sp,sa) that are predicted to achieve the power setpoints for campus 402 (e.g., P_(sp,CPO), P_(sp,AHU), P_(sp,VRF), P_(sp,RTU), P_(sp,campus)). In other words, tracking controller 612 may generate a zone temperature setpoint T_(sp,zone) and/or a supply air temperature setpoint T_(sp,sa) that cause campus 402 to consume the optimal amount of power P_(campus) determined by economic controller 610.

In some embodiments, tracking controller 612 relates the power consumption of campus 402 to the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone) using a power consumption model. For example, tracking controller 612 can use a model of equipment controller 614 to determine the control action performed by equipment controller 614 as a function of the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone). An example of such a zone regulatory controller model is shown in the following equation:

ν_(air)=ƒ₃(T _(zone) ,T _(sp,zone))

where ν_(air) is the rate of airflow to the building zone (i.e., the control action). The zone regulatory controller model may be generated by constraint generator 620 and implemented as a constraint on the optimization problem.

In some embodiments, ν_(air) depends on the speed of a fan of an AHU or RTU used to provide airflow to buildings 404 and may be a function of P_(AHU) or P_(RTU). Tracking controller 612 can use an equipment model or manufacturer specifications for the AHU or RTU to translate ν_(air) into a corresponding power consumption value P_(AHU) or P_(RTU). Accordingly, tracking controller 612 can define the power consumption P_(campus) of campus 402 as a function of the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone). An example of such a model is shown in the following equation:

P _(campus)=ƒ₄(T _(zone) ,T _(sp,zone))

The function ƒ₄ can be identified from data. For example, tracking controller 612 can collect measurements of P_(campus) and T_(zone) and identify the corresponding value of T_(sp,zone). Tracking controller 612 can perform a system identification process using the collected values of P_(campus), T_(zone), and T_(sp,zone) as training data to determine the function ƒ₄ that defines the relationship between such variables. The zone temperature model may be generated by constraint generator 620 and implemented as a constraint on the optimization problem.

Tracking controller 612 may use a similar model to determine the relationship between the total power consumption P_(campus) of campus 402 and the supply air temperature setpoint T_(sp,sa). For example, tracking controller 612 can define the power consumption P_(campus) of campus 402 as a function of the zone temperature T_(zone) and the supply air temperature setpoint T_(sp,zone). An example of such a model is shown in the following equation:

P _(campus)=ƒ₅(T _(zone) ,T _(sp,sa))

The function ƒ₅ can be identified from data. For example, tracking controller 612 can collect measurements of P_(campus) and T_(zone) and identify the corresponding value of T_(sp,sa). Tracking controller 612 can perform a system identification process using the collected values of P_(campus), T_(zone), and T_(sp,sa) as training data to determine the function ƒ₅ that defines the relationship between such variables. The power consumption model may be generated by constraint generator 620 and implemented as a constraint on the optimization problem.

Tracking controller 612 can use the relationships between P_(campus), T_(sp,zone), and T_(sp,sa) to determine values for T_(sp,zone) and T_(sp,sa). For example, tracking controller 612 can receive the value of P_(campus) as an input from economic controller 610 (i.e., P_(sp,campus)) and can use the value of P_(campus) to determine corresponding values of T_(sp,zone) and T_(sp,sa). Tracking controller 612 can provide the values of T_(sp,zone) and T_(sp,sa) as outputs to equipment controller 614.

In some embodiments, tracking controller 612 uses the battery power setpoint P_(sp,bat) to determine the optimal rate Bat_(C/D) at which to charge or discharge battery 414. For example, the battery power setpoint P_(sp,bat) may define a power value (kW) which can be translated by tracking controller 612 into a control signal for battery power inverter 416 and/or equipment controller 614. In other embodiments, the battery power setpoint P_(sp,bat) is provided directly to battery power inverter 416 and used by battery power inverter 416 to control the battery power P_(bat).

Equipment Controller

Equipment controller 614 can use the optimal temperature setpoints T_(sp,zone) or T_(sp,sa) generated by tracking controller 612 to generate control signals for campus 402. The control signals generated by equipment controller 614 may drive the actual (e.g., measured) temperatures T_(zone) and/or T_(sa) to the setpoints. Equipment controller 614 can use any of a variety of control techniques to generate control signals for campus 402. For example, equipment controller 614 can use state-based algorithms, extremum seeking control (ESC) algorithms, proportional-integral (PI) control algorithms, proportional-integral-derivative (PID) control algorithms, model predictive control (MPC) algorithms, or other feedback control algorithms, to generate control signals for campus 402.

The control signals may include on/off commands, speed setpoints for fans or compressors, position setpoints for actuators and valves, or other operating commands for individual devices of building equipment and/or central plant equipment. In some embodiments, equipment controller 614 uses a feedback control technique (e.g., PID, ESC, MPC, etc.) to adjust the operation of central plant 406 to drive the measured temperatures T_(zone) and/or T_(sa) to the temperature setpoints T_(sp,zone) and/or T_(sp,sa). Similarly, equipment controller 614 can use a feedback control technique to control the equipment of buildings 404 (e.g., AHUs, RTUs, VRF equipment, etc.) to drive the measured temperatures T_(zone) and/or T_(sa) to the temperature setpoints T_(sp,zone) and/or T_(sp,sa). Equipment controller 614 can provide the control signals to the equipment of campus 402 to control the operation of such equipment, thereby causing the equipment of campus 402 to affect the zone temperature T_(zone) and/or the supply air temperature T_(sa).

In some embodiments, equipment controller 614 is configured to provide control signals to battery power inverter 416. The control signals provided to battery power inverter 416 can include a battery power setpoint P_(sp,bat) and/or the optimal charge/discharge rate Bat_(C/D). Equipment controller 614 can be configured to operate battery power inverter 416 to achieve the battery power setpoint P_(sp,bat). For example, equipment controller 614 can cause battery power inverter 416 to charge battery 414 or discharge battery 414 in accordance with the battery power setpoint P_(sp,bat).

Constraint Generator

Still referring to FIG. 6, predictive controller 420 is shown to include a constraint generator 620. Constraint generator 620 can be configured to generate and impose constraints on the optimization processes performed by economic controller 610 and tracking controller 612. For example, constraint generator 620 can impose inequality constraints and equality constraints on the optimization of the predictive cost function J performed by economic controller 610 to generate optimal power setpoints. Constraint generator 620 can also impose constraints on the optimization performed by tracking controller 612 to generate optimal temperature setpoints.

In some embodiments, the constraints generated by constraint generator 620 include constraints on the temperature T_(zone) of buildings 404. Constraint generator 620 can be configured to generate a constraint that requires economic controller 610 to maintain the actual or predicted temperature T_(zone) between an minimum temperature bound T_(min) and a maximum temperature bound T_(max) (i.e., T_(min)≤T_(zone)≤T_(max)) at all times. The parameters T_(min) and T_(max) may be time-varying to define different temperature ranges at different times (e.g., an occupied temperature range, an unoccupied temperature range, a daytime temperature range, a nighttime temperature range, etc.).

In order to ensure that the zone temperature constraint is satisfied, constraint generator 620 can model the zone temperature T_(zone) of buildings 404 as a function of the decision variables optimized by economic controller 610. In some embodiments, constraint generator 620 models T_(zone) using a heat transfer model. For example, the dynamics of heating or cooling buildings 404 can be described by the energy balance:

${C\frac{{dT}_{zone}}{dt}} = {{- {H\left( {T_{zone} - T_{a}} \right)}} + {\overset{.}{Q}}_{HVAC} + {\overset{.}{Q}}_{other}}$

where C is the thermal capacitance of the building zone, H is the ambient heat transfer coefficient for the building zone, T_(zone) is the temperature of the building zone, T_(a) is the ambient temperature outside the building zone (e.g., the outside air temperature), {dot over (Q)}_(HVAC) is the amount of heating applied to the building zone by the HVAC equipment of buildings 404, and {dot over (Q)}_(other) is the external load, radiation, or other disturbance experienced by the building zone. In the previous equation, {dot over (Q)}_(HVAC) represents heat transfer into the building zone (i.e., the heating load) and therefore has a positive sign. However, if cooling is applied to the building zone rather than heating, the sign on {dot over (Q)}_(HVAC) can be switched to a negative sign such that {dot over (Q)}_(HVAC) represents the amount of cooling applied to the building zone (i.e., the cooling load).

In some embodiments, the amount of heating or cooling {dot over (Q)}_(HVAC) provided to buildings 404 can be defined as the heating or cooling load on the HVAC equipment of buildings 404 (e.g., RTUs, AHUs, VRF systems, etc.) and/or central plant 406. Several techniques for developing zone temperature models and relating the zone temperature T_(zone) to the decision variables in the predictive cost function J are described in greater detail in U.S. Pat. No. 9,436,179 granted Sep. 6, 2016, U.S. patent application Ser. No. 14/694,633 filed Apr. 23, 2015, and U.S. patent application Ser. No. 15/199,910 filed Jun. 30, 2016. The entire disclosure of each of these patents and patent applications is incorporated by reference herein.

The previous energy balance combines all mass and air properties of the building zone into a single zone temperature. Other heat transfer models which can be used by economic controller 610 include the following air and mass zone models:

$C_{z} = {\frac{{dT}_{zone}}{dt} = {{H_{az}\left( {T_{a} - T_{zone}} \right)} + {H_{mz}\left( {T_{m} - T_{zone}} \right)} + {\overset{.}{Q}}_{HVAC} + {\overset{.}{Q}}_{other}}}$ ${C_{m}\frac{{dT}_{m}}{dt}} = {H_{mz}\left( {T_{zone} - T_{m}} \right)}$

where C_(z) and T_(zone) are the thermal capacitance and temperature of the air in the building zone, T_(a) is the ambient air temperature, H_(az) is the heat transfer coefficient between the air of the building zone and ambient air outside the building zone (e.g., through external walls of the building zone), C_(m) and T_(m) are the thermal capacitance and temperature of the non-air mass within the building zone, and H_(mz) is the heat transfer coefficient between the air of the building zone and the non-air mass.

The previous equation combines all mass properties of the building zone into a single zone mass. Other heat transfer models which can be used by economic controller 610 include the following air, shallow mass, and deep mass zone models:

${C_{z}\frac{{dT}_{zone}}{dt}} = {{H_{az}\left( {T_{a} - T_{zone}} \right)} + {H_{sz}\left( {T_{s} - T_{zone}} \right)} + {\overset{.}{Q}}_{HVAC} + {\overset{.}{Q}}_{other}}$ ${C_{s}\frac{{dT}_{s}}{dt}} = {{H_{sz}\left( {T_{zone} - T_{s}} \right)} + {H_{ds}\left( {T_{d} - T_{s}} \right)}}$ ${C_{d}\frac{{dT}_{d}}{dt}} = {H_{ds}\left( {T_{s} - T_{d}} \right)}$

where C_(z) and T_(zone) are the thermal capacitance and temperature of the air in the building zone, T_(a) is the ambient air temperature, H_(az) is the heat transfer coefficient between the air of the building zone and ambient air outside the building zone (e.g., through external walls of the building zone), C_(s) and T_(s) are the thermal capacitance and temperature of the shallow mass within the building zone, H_(sz) is the heat transfer coefficient between the air of the building zone and the shallow mass, C_(d) and T_(d) are the thermal capacitance and temperature of the deep mass within the building zone, and H_(ds) is the heat transfer coefficient between the shallow mass and the deep mass.

In some embodiments, constraint generator 620 uses the weather forecasts from weather service 618 to determine appropriate values for the ambient air temperature T_(a) and/or the external disturbance {dot over (Q)}_(other) at each time step of the optimization period. Values of C and H can be specified as parameters of the building zone, received from tracking controller 612, received from a user, retrieved from memory 608, or otherwise provided as an input to constraint generator 620. Accordingly, the temperature of the building zone T_(zone) can be defined as a function of the amount of heating or cooling {dot over (Q)}_(HVAC) applied to the building zone using any of these heat transfer models. The manipulated variable {dot over (Q)}_(HVAC) can be adjusted by economic controller 610 by adjusting the variables P_(CPO), P_(RTU), P_(VRF), and/or P_(AHU) in the predictive cost function J.

In some embodiments, constraint generator 620 uses a model that defines the amount of heating or cooling {dot over (Q)}_(HVAC) applied to the building zone as a function of the power setpoints P_(sp,grid) and P_(sp,bat) provided by economic controller 610. For example, constraint generator 620 can add the power setpoints P_(sp,grid) and P_(sp,bat) to the green power generation P_(green) to determine the total amount of power P_(campus) that will be consumed by campus 402. In some embodiments, P_(campus) is equivalent to the combined power consumption of buildings 404 and central plant 406 (e.g., P_(campus)=P_(CPO)+P_(AHU)+P_(VRF)+P_(RTU)). Constraint generator 620 can use P_(campus) in combination with the subplant curves for central plant 406 and the equipment performance curves for the HVAC equipment of buildings 404 the total amount of heating or cooling {dot over (Q)}_(HVAC) applied to the building zone.

In some embodiments, constraint generator 620 uses one or more models that define the amount of heating or cooling applied to the building zone (i.e., {dot over (Q)}_(HVAC)) as a function of the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone) as shown in the following equation:

{right arrow over (Q)} _(HVAC)=ƒ(T _(zone) ,T _(sp,zone))

The models used by constraint generator 620 can be imposed as optimization constraints to ensure that the amount of heating or cooling {dot over (Q)}_(HVAC) provided is not reduced to a value that would cause the zone temperature T_(zone) to deviate from an acceptable or comfortable temperature range.

In some embodiments, constraint generator 620 relates the amount of heating or cooling {dot over (Q)}_(HVAC) to the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone) using multiple models. For example, constraint generator 620 can use a model of equipment controller 614 to determine the control action performed by equipment controller 614 as a function of the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone). An example of such a zone regulatory controller model is shown in the following equation:

ν_(air)=ƒ₁(T _(zone) ,T _(sp,zone))

where ν_(air) is the rate of airflow to the building zone (i.e., the control action). In some embodiments, ν_(air) depends on the speed of an AHU fan or RTU fan and may be a function of P_(AHU) and/or P_(RTU). Constraint generator 620 can use an equipment model or manufacturer specifications for the AHU or RTU to define ν_(air) as a function of P_(AHU) or P_(RTU). The function ƒ₁ can be identified from data. For example, constraint generator 620 can collect measurements of ν_(air) and T_(zone) and identify the corresponding value of T_(sp,zone.) Constraint generator 620 can perform a system identification process using the collected values of ν_(air), T_(zone), and T_(sp,zone) as training data to determine the function ƒ₁ that defines the relationship between such variables.

Constraint generator 620 can use an energy balance model relating the control action ν_(air) to the amount of heating or cooling {dot over (Q)}_(HVAC) provided to buildings 404 as shown in the following equation:

{dot over (Q)} _(HVAC)=ƒ₂(ν_(air))

where the function ƒ₂ can be identified from training data. Constraint generator 620 can perform a system identification process using collected values of ν_(air) and {dot over (Q)}_(HVAC) to determine the function ƒ₂ that defines the relationship between such variables.

In some embodiments, a linear relationship exists between {dot over (Q)}_(HVAC) and ν_(air). Assuming an ideal proportional-integral (PI) controller and a linear relationship between {dot over (Q)}_(HVAC) and ν_(air), a simplified linear controller model can be used to define the amount of heating or cooling {dot over (Q)}_(HVAC) provided to buildings 404 as a function of the zone temperature T_(zone) and the zone temperature setpoint T_(sp,zone). An example of such a model is shown in the following equations:

${\overset{.}{Q}}_{HVAC} = {{\overset{.}{Q}}_{ss} + {K_{c}\left\lbrack {ɛ + {\frac{1}{\tau_{I}}{\overset{t}{\int\limits_{0}}{{ɛ\left( t^{\prime} \right)}{dt}^{\prime}}}}} \right\rbrack}}$ ɛ = T_(sp, zone) − T_(zone)

where {dot over (Q)}_(ss) is the steady-state rate of heating or cooling rate, K_(c) is the scaled zone PI controller proportional gain, τ_(I) is the zone PI controller integral time, and ε is the setpoint error (i.e., the difference between the zone temperature setpoint T_(sp,zone) and the zone temperature T_(zone)). Saturation can be represented by constraints on {dot over (Q)}_(HVAC). If a linear model is not sufficiently accurate to model equipment controller 614, a nonlinear heating/cooling duty model can be used instead.

In addition to constraints on the zone temperature T_(zone,) constraint generator 620 can impose constraints on the state-of-charge (SOC) and charge/discharge rates of battery 414. In some embodiments, constraint generator 620 generates and imposes the following power constraints on the predictive cost function J:

P _(bat) ≤P _(rated)

−P _(bat) ≤P _(rated)

where P_(bat) is the amount of power discharged from battery 414 and P_(rated) is the rated battery power of battery 414 (e.g., the maximum rate at which battery 414 can be charged or discharged). These power constraints ensure that battery 414 is not charged or discharged at a rate that exceeds the maximum possible battery charge/discharge rate P_(rated).

In some embodiments, constraint generator 620 generates and imposes one or more capacity constraints on the predictive cost function J The capacity constraints may be used to relate the battery power P_(bat) charged or discharged during each time step to the capacity and SOC of battery 414. The capacity constraints may ensure that the capacity of battery 414 is maintained within acceptable lower and upper bounds at each time step of the optimization period. In some embodiments, constraint generator 620 generates the following capacity constraints:

C _(a)(k)−P _(bat)(k)Δt≤C _(rated)

C _(a)(k)−P _(bat)(k)Δt≥0

where C_(a)(k) is the available battery capacity (e.g., kWh) at the beginning of time step k, P_(bat)(k) is the rate at which battery 414 is discharged during time step k (e.g., kW), Δt is the duration of each time step, and C_(rated) is the maximum rated capacity of battery 414 (e.g., kWh). The term P_(bat)(k)Δt represents the change in battery capacity during time step k. These capacity constraints ensure that the capacity of battery 414 is maintained between zero and the maximum rated capacity C_(rated).

In some embodiments, constraint generator 620 generates and imposes one or more power constraints. For example, economic controller 610 can be configured to generate a constraint which limits the power P_(campus) provided to campus 402 between zero and the maximum power throughput P_(campus,max) of POI 410, as shown in the following equation:

0≤P _(campus)(k)≤P _(campus,max)

P _(campus)(k)=P _(sp,grid)(k)+P _(sp,bat)(k)+P _(green(k))

where the total power P_(campus) provided to campus 402 is the sum of the grid power setpoint P_(sp,grid), the battery power setpoint P_(sp,bat), and the green power generation P_(green).

In some embodiments, constraint generator 620 generates and imposes one or more capacity constraints on the operation of central plant 406. For example, heating may be provided by heater subplant 202 and cooling may be provided by chiller subplant 206. The operation of heater subplant 202 and chiller subplant 206 may be defined by subplant curves for each of heater subplant 202 and chiller subplant 206. Each subplant curve may define the resource production of the subplant (e.g., tons refrigeration, kW heating, etc.) as a function of one or more resources consumed by the subplant (e.g., electricity, natural gas, water, etc.). Several examples of subplant curves which can be used by constraint generator 620 are described in greater detail in U.S. patent application Ser. No. 14/634,609 filed Feb. 27, 2015.

Neural Network Modeling

Referring now to FIG. 7, a block diagram illustrating constraint generator 620 in greater detail is shown, according to an exemplary embodiment. Constraint generator 620 is shown to include a neural network modeler 706, an inequality constraint generator 708, and an equality constraint generator 710. In some embodiments, one or more components of constraint generator 620 are combined into a single component. However, the components are shown separated in FIG. 7 for ease of explanation.

Neural network modeler 706 may be configured to generate a neural network model that can be used to generate constraints for the optimization procedures performed by economic controller 610 and/or tracking controller 612. In some embodiments, the neural network model is a convolutional neural network (CNN). A CNN is a type of feed-forward artificial neural network in which the connectivity pattern between its neurons is inspired by the organization of the animal visual cortex. Individual cortical neurons respond to stimuli in a restricted region of space known as the receptive field. The receptive fields of different neurons partially overlap such that they tile the visual field. The response of an individual neuron to stimuli within its receptive field can be approximated mathematically by a convolution operation. The CNN is also known as shift invariant or space invariant artificial neural network (SIANN), which is named based on its shared weights architecture and translation invariance characteristics. Various network types are possible in various embodiments.

Referring now to FIG. 8, an example of a CNN 800 which can be generated and used by neural network modeler 706 is shown, according to an exemplary embodiment. CNN 800 is shown to include a sequence of layers including an input layer 802, a convolutional layer 804, a rectified linear unit (ReLU) layer 806, a pooling layer 808, and a fully connected layer 810 (i.e., an output layer). Each of layers 802-810 may transform one volume of activations to another through a differentiable function. Layers 802-810 can be stacked to form CNN 800. Unlike a regular (i.e., non-convolutional) neural network, layers 802-810 may have neurons arranged in 3 dimensions: width, height, depth. The depth of the neurons refers to the third dimension of an activation volume, not to the depth of CNN 800, which may refer to the total number of layers in CNN 800. Some neurons in one or more of layers of CNN 800 may only be connected to a small region of the layer before or after it, instead of all of the neurons in a fully-connected manner. In some embodiments, the final output layer of CNN 800 (i.e., fully-connected layer 810) is a single vector of class scores, arranged along the depth dimension.

In some embodiments, CNN 800 can be used to generate temperature bounds for a building zone (e.g., minimum and maximum allowable temperatures or temperature setpoints for the building zone). The temperature bounds can then be used by inequality constraint generator 708 and/or equality constraint generator 710 to generate and impose a temperature constraint for the predicted building zone temperature. In some embodiments, CNN 800 can be used to generate temperature bounds for a chilled water output produced by chillers of central plant 406 (e.g., minimum and maximum allowable temperatures of the chilled water output or chilled water setpoint). The temperature bounds can then be used by inequality constraint generator 708 and/or equality constraint generator 710 to generate and impose temperature constraints for the chilled water output or setpoint used by chillers of central plant 406. In some embodiments, CNN 800 can be used to generate temperature bounds for a hot water output produced by boilers or other hot water generators of central plant 406 (e.g., minimum and maximum allowable temperatures of the hot water output or hot water setpoint). The temperature bounds can then be used by inequality constraint generator 708 and/or equality constraint generator 710 to generate and impose temperature constraints for the hot water output or setpoint used by the boilers or other hot water generators of central plant 406. Although these specific examples are discussed in detail, it should be understood that CNN 800 can be used to generate values any other constraint on the optimization procedures performed by economic controller 610 and/or tracking controller 612.

Input layer 802 is shown to include a set of input neurons 801. Each of input neurons 801 may correspond to a variable that can be monitored by neural network modeler 706 and used as an input to CNN 800. For example, input neurons 801 may correspond to variables such as outdoor air temperature (OAT) (e.g., a temperature value in degrees F. or degrees C.), the day of the week (e.g., 1=Sunday, 2=Monday, . . . , 7=Saturday), the day of the year (e.g., 0=January 1st, 1=January 2nd, . . . , 365=December 31st), a binary occupancy value for a building zone (e.g., 0=unoccupied, 1=occupied), a percentage of occupancy for the building zone (e.g., 0% if the building zone is unoccupied, 30% of the building zone is at 30% of maximum occupancy, 100% of the building zone is fully occupied, etc.), a measured temperature of the building zone (e.g., a temperature value in degrees F. or degrees C.), operating data from building equipment 702 or central plant 406 (e.g., an operating capacity of an AHU that provides airflow to the building zone, a valve position of a flow control valve that regulates flow of the heated or chilled fluid through a heat exchanger, etc.), or any other variable that may be relevant to generating appropriate temperature bounds.

Convolutional layer 804 may receive input from input layer 802 and provide output to ReLU layer 806. In some embodiments, convolutional layer 804 is the core building block of CNN 800. The parameters of convolutional layer 804 may include a set of learnable filters (or kernels), which have a small receptive field, but extend through the full depth of the input volume. During the forward pass, each filter may be convolved across the width and height of the input volume, computing the dot product between the entries of the filter and entries within input layer 802 and producing a 2-dimensional activation map of that filter. As a result, CNN 800 learns filters that activate when it detects some specific type of feature indicated by input layer 802. Stacking the activation maps for all filters along the depth dimension forms the full output volume of convolutional layer 804. Every entry in the output volume can thus also be interpreted as an output of a neuron that looks at a small region in input layer 802 and shares parameters with neurons in the same activation map. In some embodiments, CNN 800 includes more than one convolutional layer 804.

ReLU layer 806 may receive input from convolutional layer 804 and may provide output to fully connected layer 810. ReLU is the abbreviation of Rectified Linear Units. ReLu layer 806 may apply a non-saturating activation function such as ƒ (x)=max(0, x) to the input from convolutional layer 804. ReLU layer 806 may function to increase the nonlinear properties of the decision function and of the overall network without affecting the receptive fields of convolutional layer 804. Other functions can also used in ReLU layer 806 to increase nonlinearity including, for example, the saturating hyperbolic tangent ƒ (x)=tanh(x) or ƒ (x)=|tanh(x)| and the sigmoid function ƒ (x)=(1+e^(−x))⁻¹. The inclusion of ReLU layer 806 may cause CNN 800 to train several times faster without a significant penalty to generalization accuracy.

Pooling layer 808 may receive input from ReLU layer 806 and provide output to fully connected layer 810. Pooling layer 808 can be configured to perform a pooling operation on the input received from ReLU layer 806. Pooling is a form of non-linear down-sampling. Pooling layer 808 can use any of a variety of non-linear functions to implement pooling, including for example max pooling. Pooling layer 808 can be configured to partition the input from ReLU layer 806 into a set of non-overlapping sub-regions and, for each such sub-region, output the maximum. The intuition is that the exact location of a feature is less important than its rough location relative to other features. Pooling layer 808 serves to progressively reduce the spatial size of the representation, to reduce the number of parameters and amount of computation in the network, and hence to also control overfitting. Accordingly, pooling layer 808 provides a form of translation invariance.

In some embodiments, pooling layer 808 operates independently on every depth slice of the input and resizes it spatially. For example, pooling layer 808 may include filters of size 2×2 applied with a stride of 2 down-samples at every depth slice in the input by 2 along both width and height, discarding 75% of the activations. In this case, every max operation is over 4 numbers. The depth dimension remains unchanged. In addition to max pooling, pooling layer 808 can also perform other functions, such as average pooling or L2-norm pooling.

In some embodiments, CNN 800 includes multiple instances of convolutional layer 804, ReLU layer 806, and pooling layer 808. For example, pooling layer 808 may be followed by another instance of convolutional layer 804, which may be followed by another instance of ReLU layer 806, which may be followed by another instance of pooling layer 808. Although only one set of layers 804-808 is shown in FIG. 8, it is understood that CNN 800 may include one or more sets of layers 804-808 between input layer 802 and fully-connected layer 810. Accordingly, CNN 800 may be an “M-layer” CNN, where M is the total number of layers between input layer 802 and fully connected layer 810.

Fully connected layer 810 is the final layer in CNN 800 and may be referred to as an output layer. Fully connected layer 810 may follow one or more sets of layers 804-808 and may be perform the high-level reasoning in CNN 800. In some embodiments, output neurons 811 in fully connected layer 810 may have full connections to all activations in the previous layer (i.e., an instance of pooling layer 808). The activations of output neurons 811 can hence be computed with a matrix multiplication followed by a bias offset. In some embodiments, output neurons 811 within fully connected layer 810 are arranged as a single vector of class scores along the depth dimension of CNN 800.

In some embodiments, each of output neurons 811 represents a threshold value (e.g., a boundary value, a boundary range around a setpoint, etc.) which can be used to formulate a constraint on the optimization procedures performed by economic controller 610 and/or tracking controller 612. For example, one or more of output neurons 811 may represent temperature bounds for a building zone (e.g., minimum and maximum allowable temperatures or temperature setpoints for the building zone). The temperature bounds can be used by inequality constraint generator 708 and/or equality constraint generator 710 to generate and impose a temperature constraint for the predicted building zone temperature.

In some embodiments, one or more of output neurons 811 represent temperature bounds for a chilled water output produced by chillers of central plant 406 (e.g., minimum and maximum allowable temperatures of the chilled water output or chilled water setpoint). The temperature bounds can be used by inequality constraint generator 708 and/or equality constraint generator 710 to generate and impose temperature constraints for the chilled water output or setpoint used by chillers of central plant 406. Similarly, one or more of output neurons 8110 may represent temperature bounds for a hot water output produced by boilers or other hot water generators of central plant 406 (e.g., minimum and maximum allowable temperatures of the hot water output or hot water setpoint). The temperature bounds can be used by inequality constraint generator 708 and/or equality constraint generator 710 to generate and impose temperature constraints for the hot water output or setpoint used by the boilers or other hot water generators of central plant 406.

Referring again to FIG. 7, neural network modeler 706 can use various inputs to evaluate and score the constraints generated by CNN 800. Such inputs may include operating data from building equipment 702, operating data from central plant 406, and/or user input from user devices 704. In some embodiments, the user input from user devices 704 includes manual overrides, setpoint adjustments, manual values for parameters, or other input that describes user actions. Neural network modeler 706 can use the user input from user devices 704 to determine whether the operating state of building equipment 702 and/or central plant 406 at a given time was satisfactory or whether adjustment was required. Neural network modeler 706 can use these and other types of user input to identify how people react to the constraints generated by constraint generator 620 to determine which constraint values are desired.

For example, the output of CNN 800 may include temperature bounds for a building zone. The temperature bounds may specify that the temperature of the building zone is allowed vary within an allowable temperature range between a minimum zone temperature and a maximum zone temperature. Accordingly, predictive controller 420 may operate building equipment 702 and/or central plant 406 to ensure that the temperature of the building zone is maintained between the minimum zone temperature and the maximum zone temperature. To score the temperature bounds generated by constraint generator 620, neural network modeler 706 may inspect user input indicating a manual adjustment to the temperature setpoint for a building zone. In response to the manual setpoint adjustment, neural network modeler 706 may determine that the previous temperature setpoint (i.e., the temperature setpoint generated by predictive controller 420, prior to adjustment) was out of the desirable range.

In some embodiments, neural network modeler 706 uses the magnitude of the manual setpoint adjustment as an indication of the user's dissatisfaction with the temperature setpoint generated by predictive controller 420 based on the temperature constraints generated by constraint generator 620. For example, a manual setpoint adjustment having a large magnitude may indicate a large dissatisfaction with the temperature constraints generated by constraint generator 620 and therefore may result in a low performance score. A manual setpoint adjustment having a small magnitude may indicate a slight dissatisfaction with the temperature constraints generated by constraint generator 620 and therefore may result in a relatively higher performance score. The absence of a manual setpoint adjustment may indicate user satisfaction with the temperature constraints generated by constraint generator 620 and therefore may result in a high performance score.

As another example, the output of CNN 800 may include temperature bounds for the chilled water output by chillers of central plant 406. The temperature bounds may specify that the chilled water temperature (or temperature setpoint) is allowed to vary within an allowable temperature range between a minimum chilled water temperature and a maximum chilled water temperature. Accordingly, predictive controller 420 may operate the chillers of central plant 406 to ensure that the temperature of chilled water output (or temperature setpoint) is maintained between the minimum chilled water temperature and the maximum chilled water temperature.

To score the temperature bounds generated by constraint generator 620, neural network modeler 706 may use operating data from building equipment 702 to determine whether any heat exchangers are making full use of the chilled water. For example, the operating data from building equipment 702 may indicate the valve positions of flow control valves that regulate the flow of the chilled water through cooling coils or other heat exchangers. If the operating data indicates that a flow control valve is fully open, then that valve is making full use of the chilled water. Conversely, if the operating data indicates that none of the flow control valves are fully open, then none of the flow control valves are making full use of the chilled water (i.e., none of the heat exchangers require the full cooling capacity provided by the chilled water).

In some embodiments, neural network modeler 706 uses the positions of the flow control valves as an indication of whether the chilled water temperature constraints are good or bad. For example, if none of the valves are fully open, neural network modeler 706 may determine that the chilled water temperature setpoint can be increased to reduce the energy consumption of the chillers without impacting the cooling performance of building equipment 702. The chilled water temperature can be increased until at least one of the valves is fully open to make most efficient use of the chilled water. Accordingly, neural network modeler 706 can identify the valve that is closest to fully open and can determine the difference in position between the position of that valve (e.g., 60% open) and a fully open position (e.g., 100% open). A large difference in valve position may result in a low performance score, whereas a small difference in valve position may result in a high performance score. The same scoring technique can be applied to the hot water temperature bounds generated by constraint generator 620.

Inequality constraint generator 708 and equality constraint generator 710 can use the neural network model created by neural network modeler 706 to generate inequality constraints and equality constraints. Constraint generator 620 can provide the inequality constraints and equality constraints to economic controller 610 to constrain the optimization of the predictive cost function J performed by economic controller 610 to generate optimal power setpoints. Constraint generator 620 can also provide the inequality constraints and the equality constraints to tracking controller 612 to constrain the optimization performed by tracking controller 612 to generate optimal temperature setpoints.

In some embodiments, constraint generators 708-710 use the operating data from building equipment 702 to generate various functions that define the operational domain of building equipment 702. Similarly, the operating data from central plant 406 can be used to identify relationships between the inputs and outputs of each subplant of central plant 406 and/or each device of central plant 406. Constraint generators 708-710 can use the operating data from central plant 406 to generate various functions that define the operational domains of central plant 406.

In some embodiments, constraint generators 708-710 use the operating data from building equipment 702 and central plant 406 to determine limits on the operation of building equipment 702 and central plant 406. For example, a chiller may have a maximum cooling capacity which serves as a limit on the amount of cooling that the chiller can produce. Constraint generators 708-710 can use the operating data to determine the point at which the cooling provided by the chiller reaches its maximum value (e.g., by identifying the point at which the cooling output ceases to be a function of the load setpoint) in order to determine the maximum operating limit for the chiller. Similar processes can be used to identify the maximum operating points for other devices of building equipment 702 and central plant 406. These operating limits can be used by inequality constraint generator 708 to generate inequality constraints that limit the operation of building equipment 702 and central plant 406 within the applicable limits.

Referring now to FIG. 9, a graph 8900 illustrating fixed minimum and maximum comfort bounds that a zone may operate based on under a current MPC algorithm is shown, according to some embodiments. Graph 8900 is shown to include an upper bound 8902 and a lower bound 8904. As shown in graph 8900, the current MPC algorithm keeps values of upper bound 8902 and lower bound 8904 constant over time as MPC without integrated AI operates on fixed constraints for the whole day that it optimizes over.

Referring now to FIG. 10, a graph 8950 illustrating benefits of integrating AI with MPC on the minimum and maximum comfort bounds of FIG. 9 is shown, according to some embodiments. Graph 8950 is shown to include an upper bound 8952 and a lower bound 8954. Upper bound 8952 and lower bound 8954 can illustrate varying MPC daily comfort constraints unlike the fixed MPC daily comfort constraints shown by upper bound 8902 and lower bound 8904 as described above with reference to FIG. 9. AI can prove useful in the problem of determining appropriate constraints for the MPC algorithm. By utilizing AI, constraints (e.g., minimum and maximum comfort bounds) can be found at a higher resolution, such as hourly constraints, thereby providing benefits for both financial savings and comfort.

By using AI, constraints can be learned from the preferences of occupants who occupy a controlled zone. This is done by learning the conditions that cause an occupant to change the setpoint in a zone. For example, if the occupant increases a current temperature in a space via a thermostat, said change may indicate that the current temperature is too cold for the occupant. In this way, the AI can learn the occupant's preferences and adjust lower bound 8954 and/or upper bound 8952 accordingly. Variable comfort constraints can provide benefits to both occupant comfort and financial savings as a range between lower bound 8954 and upper bound 8952 can be varied over time. In particular, at times when occupants are expected to be in the zone (e.g., during a workday), the range may be narrower to ensure occupant comfort is maintained in the zone. However, during times when occupants are not expected to be in the zone (e.g., during the night), the range may widen such that building equipment does not need to be operated as much, thereby reducing costs. In some embodiments, an additional 6-8 percent of savings can result from the addition of AI-driven time varying comfort bounds to MPC.

Referring now to FIG. 11, a comfort controller 9000 for generating comfort constraints for use in MPC is shown, according to some embodiments. In some embodiments, comfort controller 9000 is an independent controller that can generate a neural network for quantifying occupant comfort in a zone of a building. In some embodiments, comfort controller 9000 and/or some and/or all of the components therein (e.g., data collector 9010, neural network generator 9014, etc.) are included in a separate controller.

As described in greater detail below, comfort controller 9000 can perform a zone simulation to generate data used to train a neural network. To appropriately structure a zone simulation, an occupant's comfort with regards to current zone conditions should be quantified. A predicted mean vote (PMV) index can be used as a measure of thermal comfort, and is the primary method used to asses comfort in the aforementioned zone simulation. PMV is adopted by the ISO 7730 standard. The ISO recommends maintaining PMV at level 0 with a tolerance of 0.5 as the best thermal comfort. PMV can be based on theoretical model and includes results from experimental results with approximately 1300 subjects and includes four variables: temperature T, relative humidity Φ, mean radiant temperature T_(rm), and air velocity ν. The index may also include two individual parameters: metabolic rate M and cloth index I_(cl). Based on the variables and parameters, the PMV can be calculated using Fanger's Equation as given by:

PMV=G(t _(bs) ,Φ,T _(rm) ,ν,M,I _(cl))

Ordinary values for metabolic rates and clothing insulation can be found in Tables 2 and 3 below.

Insulation clo Clothing (K · m² · W⁻¹) m²K/W Nude 0 0 Underwear- Pantyhose 0.02 0.003 pants Panties 0.03 0.005 Briefs 0.04 0.006 Pants ½ long legs 0.06 0.009 made of wool Pants long legs 0.1 0.016 Underwear - Bra 0.01 0.002 shirts Shirt sleeveless 0.06 0.009 T-shirts 0.09 0.014 Shirt with long 0.12 0.019 sleeves Half slip in nylon 0.14 0.022 Shirts Tube top 0.06 0.009 Short sleeves 0.09 0.029 Light blouse with 0.15 0.023 long sleeves Light shirt with 0.2 0.031 long sleeves Normal with long 0.25 0.039 sleeves Flannel shirt with 0.3 0.047 long sleeves Long sleeves with 0.34 0.043 turtleneck blouse Trousers Shorts 0.06 0.009 Walking shorts 0.11 0.017 Light trousers 0.2 0.031 Normal trousers 0.25 0.039 Flannel trousers 0.28 0.043 Overalls 0.28 0.043 Coveralls Daily wear, belted 0.49 0.076 Work 0.5 0.078 Highly insulating Multi component with 1.03 0.16 coveralls filling Fiber pelt 1.13 0.175 Sleeveless vest 0.12 0.019 Sweaters Thin sweater 0.2 0.031 Long thin sleeves 0.26 0.04 with turtleneck Thick sweater 0.35 0.054 Long thick sleeves 0.37 0.057 with turtleneck Jacket Vest 0.13 0.02 Light summer jacket 0.25 0.039 Smock 0.3 0.047 Jacket 0.35 0.054 Coats and over Overalls multi 0.52 0.081 jackets and over component trousers Down jacket 0.55 0.085 Coat 0.6 0.093 Parka 0.7 0.109 Sundries Socks 0.02 0.003 Thin soled shoes 0.02 0.003 Quilted fleece slippers 0.03 0.005 Thick soled shoes 0.04 0.006 Thick ankle socks 0.05 0.008 Boots 0.05 0.008 Thick long socks 0.1 0.016 Skirts, dresses Light skirt 15 cm. 0.01 0.016 above knee Light skirt 15 cm. 0.018 0.028 below knee Heavy skirt knee-length 0.25 0.039 Light dress sleeveless 0.25 0.039 Winter dress long sleeves 0.4 0.062 Sleepwear Under shorts 0.1 0.016 Short gown think strap 0.15 0.023 Long gown long sleeve 0.3 0.047 Hospital gown 0.31 0.048 Long pajamas with 0.5 0.078 long sleeve Body sleep with feet 0.72 0.112 Robes Long sleeve, 0.41 0.064 wrap, short Long sleeve, 0.53 0.082 wrap, long

TABLE 3 Typical Met Levels for Various Activities (ASHRE 1997) Activity Met Seated, quiet 1.0 Reading and writing, 1.0 seated Typing 1.1 Filing, seated 1.2 Filing, standing 1.4 Walking at 0.9 m/s 2.0 House cleaning 2.0-3.4 Exercise 3.0-4.0

Comfort controller 9000 is shown to include a communications interface 9008 and a processing circuit 9002. Communications interface 9008 may include wired or wireless interfaces (e.g., jacks, antennas, transmitters, receivers, transceivers, wire terminals, etc.) for conducting data communications with various systems, devices, or networks. For example, communications interface 9008 may include an Ethernet card and port for sending and receiving data via an Ethernet-based communications network and/or a WiFi transceiver for communicating via a wireless communications network. Communications interface 9008 may be configured to communicate via local area networks or wide area networks (e.g., the Internet, a building WAN, etc.) and may use a variety of communications protocols (e.g., BACnet, IP, LON, etc.).

Communications interface 9008 may be a network interface configured to facilitate electronic data communications between comfort controller 9000 and various external systems or devices (e.g., BMS 6706, central plant controller 6700, a user device 9018, etc.). For example, comfort controller 9000 may receive information from user device 9018 indicating an occupant setpoint change from an occupant.

Still referring to FIG. 11, processing circuit 9002 is shown to include a processor 9004 and memory 9006. Processor 9004 may be a general purpose or specific purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable processing components. Processor 9004 may be configured to execute computer code or instructions stored in memory 9006 or received from other computer readable media (e.g., CDROM, network storage, a remote server, etc.).

Memory 9006 may include one or more devices (e.g., memory units, memory devices, storage devices, etc.) for storing data and/or computer code for completing and/or facilitating the various processes described in the present disclosure. Memory 9006 may include random access memory (RAM), read-only memory (ROM), hard drive storage, temporary storage, non-volatile memory, flash memory, optical memory, or any other suitable memory for storing software objects and/or computer instructions. Memory 9006 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described in the present disclosure. Memory 9006 may be communicably connected to processor 9004 via processing circuit 9002 and may include computer code for executing (e.g., by processor 9004) one or more processes described herein. In some embodiments, some components of memory 9006 are part of a single component. However, each component of memory 9006 is shown separately for ease of explanation.

Comfort controller 9000 is shown to receive setpoint changes from user device 9018 along with setpoint changes and environmental condition measurements from a thermostat 9020. Setpoint changes can be provided by an occupant to change a current operating setpoint of building equipment. Setpoint changes can indicate a user is uncomfortable in current conditions. For example, if a setpoint change indicates a higher temperature setpoint than a current temperature setpoint, the setpoint change may indicate the current temperature setpoint is too cold. User device 9018 can include any various device via which an occupant can provide setpoint changes. For example, user device 9018 may be a phone, a computer, a laptop, etc. In some embodiments, user device 9018 is the same as thermostat 9020. Thermostat 9020 is shown to provide setpoint changes and environmental condition measurements to comfort controller 9000. The environmental condition measurements can include various measurements of temperature, humidity, air quality, etc. of the zone and/or an external space. In some embodiments, the measurements are gathered by various sensors (e.g., temperature sensors, humidity sensors, etc.) in the zone and/or the external space. In some embodiments, comfort controller 9000 receives the measurements from the sensors separate and/or in addition to the measurements provided by thermostat 9020. It should be appreciated that user device 9018 and thermostat 9020 are shown for sake of example of sources from which comfort controller 9000 can receive information. Comfort controller 9000 can receive pertinent information for generating a neural network from any suitable device, service, etc.

Comfort controller 9000 is shown to include a data collector 9010. Data collector 9010 can collect received data from communications interface 9008. The received data can include setpoint changes, environmental condition measurements, etc. Data collector 9010 can provide the collected data to a neural network generator 9014 and/or a zone simulator 9012.

In order to achieve a sufficiently trained neural network to assist in determining zone constraints, there should first be enough data to learn from. The primary data that is necessary for training the neural network can include override data from a zone (i.e., the setpoint changes shown in FIG. 11). Collecting a large amount of real data for manual setpoint changes in a zone can be difficult. In particular, the amount of time needed to gather said data may take a long time (e.g., at least a year) before setpoint changes can be predicted, thereby resulting in slow implementation of MPC for a building. Additionally, gathering real data may include an assumption that all occupants in the zone actually choose to adjust the setpoint when uncomfortable. However, this may not always be the case as some occupants may not know how to change the setpoint, be too busy to change the setpoint, etc. As such, there may not be enough occupant overrides throughout each day to train the network.

Prompts for comfort feedback can be initiated by the data collector 9010 and transmitted to the user device 9018 via communications interface 9008. In other embodiments, an application executed locally on the user device 9018 can automatically generate prompts for the user to input comfort feedback. For example, a push notification (e.g., causing the user device to ring, buzz, light up, etc.) may be provided at the user device 9018 and the user may be provide with a graphical user interface asking the user (occupant) to provide feedback relating to the user's current comfort level in the space. For example, prompts may ask the user to provide input of whether they are too cold, too hot, or comfortable. In some embodiments, users are asked to input a number of degrees hotter or colder that they would like the space to be. By pushing prompts to the user device 9018, occupants may be compelled to provide more feedback as compared to passively awaiting user changes to a setpoint for the space, for example by overcoming occupant apathy, laziness, resignation to discomfort, or other factors that may keep uncomfortable occupants from changing the temperature setpoint.

In some embodiments, multiple user devices 9018 are included and associated with multiple occupants of a space. In such embodiments, prompting comfort feedback at the user devices 9018 results in receiving votes from multiple occupants regarding whether the building is comfortable at a given time. The occupants' comfort level may differ due to occupant personal preference, clothing selections, activity levels, location relative to windows, HVAC equipment, or other appliances, and various other factors. Polling multiple occupants via a voting application can generate data that reflects the comfort of many occupants. This approach may avoid a scenario where only a subset of occupants has access or authority to change a temperature setpoint, such that the preferences of other occupants is hidden. In some embodiments, by receiving comfort feedback from multiple occupants, training data can be tagged for particular occupants and one or more neural networks can be trained to allow the system to adapt to meet the preferences of the occupants that are actually present at any given time.

In some embodiments, the data collector 9010 may facilitate the generation or collection of sufficient data by executing an experiment to deliberate control the zone temperature to a variety of values, for example including uncomfortable temperatures. By exposing occupants to more environmental conditions, the user's response to such conditions may be recorded and represented in the training data collected at the data collector 9010. For example, a sequence of setpoints (e.g., a preprogrammed sequence, a random sequence (e.g., PBRS), a dynamic sequence that reacts to comfort feedback from a user) may be applied in order to test user comfort under varying conditions. By varying conditions while collecting comfort feedback via a user device 9018 or thermostat 9020, a rich set of data suitable for training the neural network may be collected at the data collector 9010.

In one embodiment of a comfort experiment which takes place over several days, a constant setpoint is provided over entire day with a different value for each day. During each day, occupant comfort is recorded (from direct user input of comfort feedback, from comfort feedback based on attempted setpoint changes by a user, etc.). Such an experiment can provide rich data indicative of how comfort varies over the course of each day even at constant temperature, and at the same time on different days at different temperatures.

In some embodiments, to provide for generation of sufficient training data, comfort controller 9000 can include a zone simulator 9012 to model the indoor conditions in a zone, given real outdoor air conditions. Based on the simulated conditions, typical occupant setpoint overrides can be simulated as well.

Using real past weather measurements for a particular site, zone simulator 9012 can produce indoor air conditions, including zone temperatures and zone humidity ratios, for a corresponding time period. For simplicity, only temperature and humidity ratio simulations may be used for learning comfort constraints. However, additional measurements and features can be added to the AI to increase accuracy and make the overall simulation more realistic.

Another important aspect of the zone simulation performed by zone simulator 9012 is a response of occupants to the indoor air temperature and humidity. In is sense, a four variable comfort control approach can be integrated to allow the simulator to detect whether or not certain occupants would be uncomfortable given current conditions. In some embodiments, the occupant simulation includes carbon dioxide generation and/or heat effects on the zone by occupants. The variables that occupant simulation may depend on include metabolic rate, clothing insulation, and the specific occupant's comfort preferences (in terms of the PMV index). Said conditions can be combined to determine whether or not an occupant is comfortable.

As described above, each occupant simulation performed by zone simulator 9012 can include the three variables indicated above: metabolic rate, clothing insulation, and comfort preferences. In some embodiments, the occupant simulations include less variables, different variables, and/or more variables than the three indicated above.

Metabolic rates can be determined by a metabolic schedule for a particular occupant. The metabolic schedule can be structured as a specified rate with a corresponding hour. This means that at an hour provided, the occupant may begin simulation at the rate provided. The metabolic rate may change at an hour mark if a new metabolic rate is specified at said hour mark. Both the metabolic rate and the hour may be random variables, as to provide a sense of randomness if populating the training data. Randomizing the variables can better capture changes in people as a person may not have the exact same metabolic rates at the exact same times every day.

Clothing insulation can be determined by outdoor air conditions. In particular, it may be assumed that a zone occupant would be dressed heavier on colder days, and lighter on warmer days. In general, the range should not vary enormously in the zone, but there should be a seasonal feature to clothing insulation.

Occupant comfort preferences can be described by a minimum and maximum PMV index at which the occupant is comfortable. In some embodiments, a general range for comfort is considered to be from −0.5 to 0.5, however, certain people prefer colder or warmer environments than others. As such, the range for comfort can vary depending on what occupants are in the zone. Due to the fluctuation in preference, the minimum and maximum PMV bounds can be custom for each occupant, and may both be random variables to account for natural variability.

If an occupant is uncomfortable, that is, the occupant's PMV value is outside of their comfort bounds, the occupant may want to override the setpoint (e.g., move the setpoint up or down). In detail, the metabolic rate, clothing insulation, and zone temperature and humidity simulations are fed into the PMV calculation performed by zone simulator 9012, which can output an index value for the occupant in question. The PMV index can be compared to the minimum and maximum PMV comfort bounds that describe the specific occupant's preferences. If the PMV value is below the minimum comfort bound, the occupant may increase the setpoint to a temperature that results in a PMV value within their comfort bounds. Similarly, if the PMV is above the maximum comfort bound, the occupant may decrease the setpoint to a temperature that results in a PMV value within their bounds. This process can be carried out in each time-step of the simulation performed by zone simulator 9012. Every time PMV is calculated, the instantaneous zone conditions can be used to determine an occupant's comfort.

At the top of every hour in the simulation, a new setpoint can be calculated for each occupant in the zone based on their comfort in the current zone conditions. It should be appreciated that new setpoints can be calculated at different increments of time other than an hour. For example, the new setpoints can be calculated every thirty minutes, every two hours, etc. The simulation can collect all of the individual setpoints and use them to output an overall setpoint for that hour. There are many different ways for the simulation to decide what the new setpoint should be. For example, a max or mean of all occupant setpoints can be calculated. As another example, determining the new setpoint can involve a sort of occupant priority, such as weighting the setpoints of certain occupants. For example, an owner of the building may have a higher priority (e.g., a higher weight) as compared to other employees of the building. At each hour (or other time increment) of the simulation performed by zone simulator 9012, the indoor air temperature setpoint can be changed by the mean of all setpoint overrides for that hour. The setpoint changes can recorded as data to be used for training the AI and provided to neural network generator 9014.

Based on received data (e.g., collected data and/or simulated training data), neural network generator 9014 can generate a neural network that can be used to predict setpoint changes. In particular, the AI can be used to determine hourly comfort constraints that will satisfy comfort bounds of occupants in a zone. As such, the neural network can be trained using real data collected by data collector 9010 and/or simulated training data generated by zone simulator 9012 to associate various environmental conditions with occupant comfort in the zone. The neural network generated by neural network generator 9014 can be various types of neural networks such as, for example, an MLP, an RBFNN, an RNN, an autoencoder neural network, etc. An example of the neural network generated by neural network generator 9014 is shown below with reference to FIG. 12. Neural network generator 9014 can provide the trained neural network to constraint generator 9016.

Based on the neural network received from neural network generator 9014, a combination of air conditions, occupant comfort data, and information describing the type of day can be fed into a neural network by constraint generator 9016. Based on the fed inputs, the neural network can output a change in a temperature setpoint that corresponds to a particular hour and/or some other unit of time. Inputs to the neural network can include, for example, a time of day (e.g., a particular hour), season of the year, indoor air temperature, indoor humidity, information on the outdoor air conditions, etc. as received from data collector 9010. The outdoor air conditions can be described in multiple formats.

To determine the change in the temperature setpoint, one potential method is to use a separate neural network to classify a day based on outdoor air conditions. Said classification label can be fed into the neural network for setpoint change prediction to represent the outdoor air conditions for a given day. An example of the classification can be performed by neural network generator 9014 and constraint generator 9016 as follows. To perform the classification, neural network generator 9014 may, for simplicity, assume the only parameters being classified are temperature and humidity. The neural network can label days as a combination of sets. For example, the sets to be combined can be given as: {Extremely Hot, Hot, Normal, Cold, Extremely Cold} and {Extremely Humid, Humid, Normal, Dry, Extremely Dry}. Based on the sets, constraint generator 9016 can feed conditions into the separate neural network to generate classifications to use in the primary neural network (i.e., the neural network that predicts the change in temperature setpoint). For example, a particular day may be labeled as {Hot, Extremely Dry} whereas another day may be labeled as {Extremely Cold, Dry} as based on data fed into the separate neural network. Said labels can be provided to the primary neural network to predict the setpoint changes for the associated days.

Another potential method for predicting setpoint changes is to directly input outdoor air measurements into the neural network for predicting setpoint changes. For example, the neural network described below with reference to FIG. 12 can use said measurements as input. Based on the outdoor air measurements, the neural network can output the predicted change in the setpoint for a specific hour (or some other unit of time). The change in setpoint can be based upon the mean setpoint changes made by all the occupants currently in the zone. The neural network may, therefore, be a solving a problem of regression rather than classification.

It should be appreciated that both methods may provide the neural network with learnable information on how the conditions will affect the preferences of the occupants present in the zone.

With the trained neural network for predicting hourly setpoint changes (or setpoint changes for some other increment of time), the hourly comfort constraints can be determined with some post-processing. For a given day, the constraints can be found by iterating over each hour and sweeping the zone temperature to find minimum and maximum bounds for each hour. More specifically, a zone temperature range can be chosen (e.g., 15° C. to 30° C., 20° C. to 31° C., etc.), and for each hour, the trained neural network can predict the change in setpoint for that hour at each of the zone temperatures in the chosen range. For a specific hour, the minimum bound can be the lowest temperature at which the neural network predicts a setpoint change of zero. Likewise, the maximum bound can be the highest temperature at which the network predicts a change of zero. This process can result in hourly comfort constraints that can be used in the MPC algorithm. As such, constraint generator 9016 can provide the comfort constraints to the economic controller 610 and/or the tracking controller 612 via communications interface 9008, so that MPC can be performed subject to the comfort constraints via the economic controller 610 and the tracking controller 612. In some embodiments, if constraint generator 9016 and/or other components of comfort controller 9000 are part of predictive controller 420 (e.g., provided with the constraint generator 620 as in the embodiment of FIG. 6). In various embodiments, the comfort constraints can be used by a different component of predictive controller 420 for performing MPC. In other embodiments, the comfort constraints are used to constrain a predictive control process at a central plant controller, for example a central plant controller described in further detail in U.S. Provisional Application No. 62/489,975 filed Apr. 25, 2017, the entire disclosure of which is incorporated by reference herein and to which the present application claims priority. Equipment is thereby controlled in accordance with the comfort constraints generated using the trained neural network.

Referring now to FIG. 12, an illustration 9100 of a neural network model for predicting changes in setpoints is shown, according to some embodiments. In some embodiments, the neural network model of illustration 9100 is generated by neural network generator 9014 described above with reference to FIG. 11. The neural network model of illustration 9100 is shown to include an input layer 9102, a hidden layer(s) 9104, and an output layer 9106. Input layer 9102 is shown to include multiple input neurons. Each input neuron can be associated with a different variable representing a time of day, environmental conditions, etc. In particular, the input neurons are shown to receive values of a zone temperature T_(z), a zone relative humidity RH_(z), a time of day, an outdoor air temperature T_(oa), an outdoor relative humidity RH_(oa), and a season. It should be appreciated that said variables are shown for sake of example. The neural network can receive various inputs that are relevant to generate a predicted setpoint change. The neural network shown in illustration 9100 uses raw outdoor air measurements to describe outdoor air conditions.

The neural network of illustration 9100 is also shown to include hidden neurons in hidden layer(s) 9104. Depending on the type of neural network utilized, hidden layer(s) 9104 may include various numbers of hidden layers and/or various numbers of hidden neurons therein. For example, hidden layer(s) 9104 of a first neural network may include only one hidden layer with a particular number of hidden neurons, whereas hidden layer(s) 9104 of a second neural network may include more than one hidden layer, each layer having a particular number of hidden neurons. To train weights of the hidden neurons, the neural network of illustration 9100 can undergo supervised learning and training off of a dataset of setpoint changes that correspond to input data for a particular hour. In order to train the network, however, a large amount of data may be required. While gathering a sufficient amount of outdoor and indoor air measurements may be possible, gathering a sufficient amount of setpoint change output data may not be possible in a reasonable amount of time. It may be difficult to gather accurate data for this purpose, and it would also take an unreasonable amount of time to create a robust dataset. Because of said difficulty and as described above with reference to FIG. 11, the neural network can be generated based on a simulation framework set up to populate an occupant temperature override dataset.

The trained neural network can output a value of the predicted setpoint change ΔT_(sp). As described in greater detail above with reference to FIG. 11, ΔT_(sp) can be used to generate comfort constraints used in MPC.

Referring now to FIG. 13, an illustration 9150 of another embodiment of a neural network is shown, according to an exemplary embodiment. In particular, FIG. 13 shows an embodiment where input layer 9152 receives inputs including a zone temperature T_(z), a zone relative humidity RH_(z), a time of day, and a type-of-day (day-type). The type-of-day is provided in FIG. 13 in place of the season and outdoor air conditions used in the embodiment of FIG. 12. The type-of-day may be a proxy for what an occupants may be wearing in the space, user activity in the space, a number of occupants in the space, and other factors than may influence occupant comfort. For example, the type-of-day label may indicate if the day is a work day, a weekend day, a holiday, which season the day is in, an outdoor condition for that day (e.g., hot day, humid day, cold day, rainy day, snowy day, etc.). A separate neural network classifier or other program logic may be included to generate the day-type based on raw data and provide the type-of-day label to the input layer 9152.

As for the embodiment of FIG. 12, the neural network of illustration 9150 includes hidden layers 9154. Different numbers of hidden layers 9154 may be included in various embodiments, and may be configured as described above with reference to FIG. 12 (adapted to work with the input layer 9152 of FIG. 13). The neural network of illustration 9150 can be trained to provide, at the output layer 9106, a value of the predicted setpoint change ΔT_(sp) for a given zone temperature, a zone relative humidity, a time of day, and a type-of-day.

Referring now to FIG. 14, a graph 9200 illustrating sweeping of a zone temperature to determine comfort constraints is shown, according to some embodiments. Graph 9200 is shown to include a series 9202 used to determine values of comfort constraints. Series 9202 can associate values of ΔT_(sp) with T_(z). To determine a lower bound of the comfort constraints, series 9202 can be swept until a change in ΔT_(sp) of zero is reached. As shown in series 9202 reaches zero at a lower bound 9204 that can define the lower bound of the comfort constraints. To identify the upper bound of the comfort constraints, series 9202 can continue to be swept past lower bound 9204 until series 9202 diverges from a ΔT_(sp) value of zero. As shown in graph 9200, said value can be determined as an upper bound 9206. In this way, lower bound 9204 and upper bound 9206 can define values of T_(min) and T_(max) to be used as comfort constraints in MPC.

Referring now to FIG. 15, a process 9300 for determining hourly comfort constraints is shown, according to some embodiments. By performing process 9300, comfort constraints can be generated for use in MPC. In general, process 9300 can result in an upper bound and a lower bound being generated for temperature. It should be appreciated, however, that process 9300 can be performed to generate constraints for other conditions such as relative humidity. Further, process 9300 can be augmented to use different increments of time other than an hour as shown. In some embodiments, some and/or all steps of process 9300 are performed by constraint generator 9016 and/or another component of comfort controller 9000 as described above with reference to FIG. 11.

Process 9300 is shown to include choosing a day (step 9302). The day selected in step 9302 can indicate a day of the week (e.g., a weekday or a weekend). The selected day can be used to predict various information such as an amount of occupants expected to be present in an associated zone. For example, a day on a weekend may be associated with fewer occupants as compared to a weekday. In some embodiments, step 9302 is performed by constraint generator 9016.

Process 9300 is shown to include setting an hour variable to midnight (step 9304). Midnight (i.e., 0:00) can function as a starting point for the day to which incremental setpoint changes can be determined. In some embodiments, a different starting point is set as the hour variable instead of midnight. If a different starting point is used, the process can instead extend for twenty-four hours from the different starting point. In some embodiments, step 9304 is performed by constraint generator 9016.

Process 9300 is shown to include a determination of if the hour variable is less than or equal to 23:00 (step 9306). As 23:00 is an hour before midnight of a next day, the process should not continue if the hour variable is beyond 23:00, otherwise process 9300 may extend into a following day. As such, if the determination is that the hour variable is greater than 23:00, process 9300 may end. If the determination is that the hour variable is less than or equal to 23:00, process 9300 can continue to step 9308. In some embodiments, step 9306 is performed by constraint generator 9016.

Process 9300 is shown to include setting a zone temperature variable to 15° C. (step 9308). It should be appreciated that 15° C. is used for sake of example. The zone temperature variable can be set to other starting points (e.g., 14° C., 16° C., 18° C., etc.). Further, other temperature scales (e.g., Fahrenheit, Kelvin, etc.) can be used instead of Celsius. In some embodiments, the zone temperature variable is initially set to a temperature that is predicted to be less than a minimum zone temperature that may result in ΔT_(sp)=0. In some embodiments, step 9308 is performed by constraint generator 9016.

Process 9300 is shown to include a determination of if the zone temperature variable is less than or equal to 30° C. (step 9310). Similar to step 9308, 30° C. is used for sake of example. In some embodiments, the value used for reference in step 9310 can be set to a value expected to be greater than a maximum zone temperature that results in ΔT_(sp)=0. In some embodiments, step 9310 is performed by constraint generator 9016.

Process 9300 is shown to include predicting ΔT_(sp) for a current hour (step 9312). Step 9312 can include using a trained neural network to predict the setpoint change based on zone conditions. In other words, the zone conditions can be input to the neural network to predict a value of ΔT_(sp) for the current hour. In some embodiments, step 9312 is performed by constraint generator 9016.

Process 9300 is shown to include incrementing T_(z) (step 9314). T_(z) can be incremented by various increment values (e.g., 0.5, 1.0, 1.5, etc.). The incremental value can be set that T_(z) does not exceed the maximum zone temperature that results in ΔT_(sp)=0 too far (if at all). After incrementing T_(z), process 9300 can repeat step 9310 and continue to step 9316. In this way, ΔT_(sp) can be predicted for multiple values of T_(z) to determine approximate values of the minimum and maximum comfort bounds. In some embodiments, step 9314 is performed by constraint generator 9016.

Process 9300 is shown to include a determination of the predicted value of ΔT_(sp)=0 (step 9316). If the determination in step 9316 is that ΔT_(sp)≠0, process 9300 may end for a current increment of T_(z). If the determination in step 9316 is that ΔT_(sp)=0, process 9300 can continue to step 9318. In some embodiments, step 9316 is performed by constraint generator 9016.

Process 9300 is shown to include setting values of a minimum and a maximum comfort bound (step 9318). In particular, the minimum comfort bound can be set to:

T _(min)=min(T _(z)(ΔT _(sp)=0))

where T_(min) is the minimum comfort bound. Further, the maximum comfort bound can be set to:

T _(max)=max(T _(z)(ΔT _(sp)=0))

where T_(max) is the maximum comfort bound. By incrementing T_(z) and applying it to the neural network to get ΔT_(sp) for each iteration of incrementing T_(z) values of ΔT_(sp) for multiple values of T_(z) are found, and then can be used to find where ΔT_(sp) changes from zero to non-zero. In this way, T_(min) can be set to a minimum value of the zone temperature where the change in the predicted setpoint is zero, whereas T_(max) can be set to a maximum value of the zone temperature where the change in the predicted setpoint is zero. In some embodiments, step 9318 is performed by constraint generator 9016.

Process 9300 is shown to include incrementing the hour variable (step 9320). The hour variable can be incremented by one hour based on which process 9300 can repeat starting at step 9306 with the incremented hour variable as well as continue to step 9322. In some embodiments, the hour variable is incremented by a different value depending on a resolution desired for values of T_(min) and T_(max). In general, as the desired resolution increases, the incremental value may decrease. In some embodiments, step 9320 is performed by constraint generator 9016.

Process 9300 is shown to include outputting the daily comfort bounds (step 9322). The outputted daily comfort bounds can be used to perform MPC such that MPC decisions do not result in occupant comfort violations. In some embodiments, step 9322 is performed by constraint generator 9016.

Referring now to FIG. 16, a flowchart of a process 1600 for training a neural network to predict comfort or discomfort of occupants of a building is shown, according to an exemplary embodiment. Process 1600 can be executed by the comfort controller 9000 in various embodiments.

At step 1602, one or more occupants are exposed to a first set of environmental conditions of a building. For example, building equipment may be controlled to provide the environmental conditions at the building. In some embodiments, step 1602 includes performing an experiment whereby the first set of environmental conditions is generated outside of normal operation of the equipment (e.g., using a random setpoint, using a setpoint schedule defined for the experiment) to deliberately test the occupants' reaction to the first set of environmental conditions.

At step 1604, the one or more occupants are prompted for comfort feedback. In some embodiments, prompting the one or more occupants for comfort feedback includes providing graphical user interfaces on user devices (e.g., smartphones, personal computers) of occupants of the building which include options for the users to provide structured feedback. In some embodiments, the prompts are provided as part of a mobile application for occupants a building, for example the Companion App by Johnson Controls. In other embodiments, for example in an office context, prompts can be automatically provided on user's computer workstations (e.g., desktop computers).

In some examples of step 1604, a user may be provided with an option in a graphical user interface to indicate that the user is hot, cold, or comfortable. As another example, the user may be prompted to indicate the user's perception of how far (e.g., a number of degrees Celsius or Fahrenheit, a subjective scale) the user is from comfort. The user can be prompted for feedback 1604 during a training period for a neural network, after which time such prompts can be stopped to allow for automatic comfort prediction as described herein.

In other embodiments, step 1604 includes providing prompts via a thermostat or a dedicated comfort feedback device positioned in the building. For example, a comfort feedback device may be provided in a space with three buttons representing hot, comfortable, and cold, such that occupants can easily provide simple comfort feedback. As another example, step 1604 may include allowing a user to input temperature setpoint changes via a thermostat or a mobile app.

At step 1606, the comfort feedback is received from the user. The comfort feedback may be received at a database as digital information which can be associated with a time stamp and stored. The comfort feedback can be associated with data representing environmental conditions and other factors at the time that the comfort feedback was provided or for the day on which the comfort feedback was provided, for example indoor air temperature, outdoor air temperature, indoor relative humidity, outdoor relative humidity, weather, day type, etc. which can be used as time-varying inputs.

At step 1608, a neural network is trained using the comfort feedback and one or more time-varying inputs to the neural network. The neural network may be trained to predict the comfort feedback given the one or more time-varying inputs, for example indoor air temperature, outdoor air temperature, indoor relative humidity, outdoor relative humidity, weather, day type.

In some embodiments, the neural network is trained to predict a temperature setpoint change ΔT_(sp) that occupants would request if subjected to the conditions defined by the set of input values. This represents a prediction of occupant comfort, where ΔT_(sp)=0 if the occupants are predicted to be comfortable, ΔT_(sp)<0 represents that the occupants are predicted to be too hot, and ΔT_(sp)>0 represents that the occupants are predicted to be too cold. The neural network is thereby trained to predict whether the occupant will be comfortable (which amounts to a prediction of whether the occupant will be uncomfortable).

In the embodiment shown, a single neural network is trained using the comfort feedback from the multiple occupants, for example such that the comfort prediction represents a composite reaction of the multiple occupants. For example, a prediction of ΔT_(sp)=0 may represent that a vote/pool conducted of the multiple occupants would have a winner of ΔT_(sp)=0 (e.g., majority pick ΔT_(sp)=0, an average change of approximately ΔT_(sp)=0). In other embodiments, multiple, separate neural networks may be trained corresponding to the different occupants (or different subsets of the multiple occupants) based on comfort feedback from the specific, corresponding occupants. In such embodiments, each neural network may be trained to predict the comfort of that particular occupant (or subset of occupants). Predictions from multiple neural networks can then be combined for use in defining composite predictions, or selected between depending which occupants are present in a building at a given time, based on a hierarchy of the occupants that gives a first occupant's comfort priority over another occupant's comfort, or some other combination or conflict resolution approach.

Process 1600 thereby outputs a trained neural network for occupant comfort prediction, which can then be applied in a process 1700 for operating a building equipment using comfort predictions, for example as shown in FIG. 17 according to an exemplary embodiment. The process 1700 can be executed by the comfort controller 9000 in some embodiments. References to comfort predictions, predictions that an occupant will be comfortable, etc. herein should be understood as also encompassing the inverse, i.e., discomfort predictions, predictions that an occupant will be uncomfortable, etc., given certain input conditions. The language herein is meant to cover formulations and approaches that use any perspective (e.g., where an occupant is predicted to be comfortable and where an occupant is predicted to be not uncomfortable).

At step 1702, one or more time-varying inputs to the neural network are determined. The time-varying inputs may include measured or forecast values of outside air conditions, weather conditions, day types, etc. The time-varying inputs may also include a test indoor air temperature (or other value for an environmental condition), which can be used to predict occupant comfort given a selected indoor air temperature or temperature setpoint (or other condition), for example using the iterative process of described above with reference to FIG. 15. In embodiments where multiple neural networks are generated corresponding to different occupants or different subsets of occupants, step 1702 can include selecting the appropriate neural network (e.g., by determining which occupants are currently present or expected to be present based on data from an access system, security system, scheduling system, or other data source).

At step 1704, the time-varying inputs are applied to the neural network to determine one or more time-varying thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable. This is equivalent to and meant to encompass formulations where the thresholds are characterized as defining limits on values for an environmental condition of the building for which one or more occupants are predicted to be uncomfortable.

In some embodiments, step 1704 includes an iterative process as in FIG. 15, where a setpoint change for the environmental condition is predicted at the output layer of the neural network, and one or more controllable inputs (e.g., a setpoint for the environmental condition) are incremented to find the controllable inputs that correspond to points where the predicted setpoint change becomes non-zero. The predicted setpoint change can become non-zero when the input value for the environmental condition becomes too high or too low, thereby providing end points of a comfort range (or, seen equivalently with the opposing polarity, thresholds of a discomfort range). In some embodiments, only a single threshold value is determined dynamically by the neural network, for example a minimum value for the environmental condition or a maximum value for the environmental condition. In such embodiments, a static second threshold may be used to define a range, or any values on one side of the single threshold value can be considered comfortable values for the environmental condition (and, corresponding, values on the other side of the single threshold value considered uncomfortable values for the environmental condition). In some embodiments, additional arithmetic or processing is performed on determined thresholds (e.g., adding constant offsets, always setting at least a minimum gap between threshold values, etc.) without deviating from the scope of generating thresholds using outputs of the neural network.

In other embodiments, the neural network may be configured such that the output layer of the neural network directly provides minimum and maximum values for a range within which the occupants are predicted to be comfortable. In yet other embodiments, the neural network may be configured such that the output layer of the neural network provides a comfort value which is used to define the range as within a deadband around the comfort value.

At step 1706, setpoints are generated for building equipment by executing a predictive control process subject to constraints based on the one or more thresholds. The setpoints generated at step 1706 may include temperature setpoints, amounts of thermal energy to be consumed, stored, or provided by equipment, fan speeds, air flow rates, compressor frequencies, among other possibilities. The predictive control process may be a model predictive control process as described above. In some implementations of step 1708, the predictive control process be an asset allocation process for a central plant as described in further detail in U.S. Provisional Application No. 62/489,975 filed Apr. 25, 2017, the entire disclosure of which is incorporated by reference herein and to which the present application claims priority.

Subject to the constraints based on the one or more thresholds, the model predictive control approach may be configured to ensure that a predicted value of the environmental condition stays between the thresholds, i.e., such that the occupants are predicted to be comfortable at the predicted value of the environmental condition. In other embodiments, the model predictive control approach may be configured to ensure that a setpoint for the environmental condition stays between the threshold, i.e., such that the occupants are predicted to be comfortable when the environmental condition has the setpoint value. The range of possible values between the two thresholds allows room for cost optimization, energy usage optimization, resource usage optimization, load shifting, etc. while constraining the environmental condition to values predicted to be comfortable to an occupant (or penalizing uncomfortable values for the environmental condition).

Step 1706 can include generating multiple setpoints for one environmental condition, for example a setpoint for each hour in a day-long optimization period. Step 1706 can also include generating setpoints for multiple different variables in various embodiments.

At step 1708, the building equipment is operated to drive the environmental condition toward the setpoints. For example, a control signal can be electronically transmitted from a controller to the equipment to cause the building equipment to operate in accordance with the control signal such that the environmental condition is driven towards the setpoint. Process 1700 can thereby result in the environmental condition being driven to a value which is predicted to be comfortable for occupants of the space while also providing for cost or energy optimization or other advantage associated with the predictive control process implemented in step 1706.

Configuration of Exemplary Embodiments

The construction and arrangement of the systems and methods as shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements can be reversed or otherwise varied and the nature or number of discrete elements or positions can be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps can be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes, and omissions can be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present disclosure.

The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure can be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.

Although the figures show a specific order of method steps, the order of the steps may differ from what is depicted. Also two or more steps can be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps. 

What is claimed is:
 1. A building control system comprising one or more controllers configured to: obtain comfort feedback provided by one or more occupants of a building under a first set of environmental conditions of the building; generate, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable; execute a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment; and operate the building equipment to drive the environmental condition of the building toward the setpoints.
 2. The building control system of claim 1, wherein the comfort feedback comprises a setpoint adjustment or a comfort vote provided by the one or more occupants during a first time period.
 3. The building control system of claim 1, wherein the one or more occupants are predicted to be comfortable in response to a prediction that the comfort feedback will satisfy a condition during a second time period.
 4. The building control system of claim 1, wherein the one or more controllers are configured to predict whether the one or more occupants will be comfortable at a value of the environmental condition using a neural network model trained with the comfort feedback and corresponding values of the first set of environmental conditions of the building.
 5. The building control system of claim 1, wherein the one or more controllers are configured to generate the one or more thresholds using a neural network comprising an input neuron for a value of the environmental condition and configured to output a predicted comfort feedback.
 6. The building control system of claim 5, wherein the one or more controllers are configured to generate the one or more thresholds by: iteratively applying a plurality of values for the environmental condition at the input neuron to obtain a plurality of predicted comfort feedbacks associated with the plurality of values for the environmental condition; determining, from the plurality of values for the environmental condition and the plurality of predicted comfort feedbacks: a maximum value for the environmental condition for which the predicted comfort feedback satisfies a condition; and a minimum value for the environmental condition for which the predicted comfort feedback satisfies a condition; and assigning the maximum value and the minimum value as the one or more thresholds.
 7. The building control system of claim 1, wherein the one or more thresholds comprise one or more time-varying values for a plurality of time steps in an optimization period.
 8. A method, comprising: obtaining comfort feedback from one or more occupants of a building while the one or more occupants are exposed to a first set of environmental conditions of the building; generating, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable; executing a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment; and operating the building equipment to drive the environmental condition of the building toward the setpoints.
 9. The method of claim 8, wherein the comfort feedback comprises setpoint adjustments provided by the one or more occupants during a first time period; and the one or more occupants are predicted to be comfortable in response to a prediction that the setpoint adjustments will satisfy a condition during a second time period.
 10. The method of claim 8, wherein the comfort feedback comprises comfort votes provided by the one or more occupants via a mobile device during a first time period; and the one or more occupants are predicted to be comfortable in response to a prediction that the comfort votes will satisfy a condition during a second time period.
 11. The method of claim 8, further comprising predicting whether the one or more occupants will be comfortable at a value of the environmental condition using a neural network model trained with the comfort feedback and corresponding values of the first set of environmental conditions of the building.
 12. The method of claim 8, wherein generating the one or more thresholds comprises using a neural network comprising an input neuron for a value of the environmental condition and configured to output a predicted comfort feedback.
 13. The method of claim 12, wherein generating the one or more thresholds comprises: iteratively applying a plurality of values for the environmental condition at the input neuron to obtain a plurality of predicted comfort feedbacks associated with the plurality of values for the environmental condition; determining, from the plurality of values for the environmental condition and the plurality of predicted comfort feedbacks: a maximum value for the environmental condition for which the predicted comfort feedback satisfies a condition; and a minimum value for the environmental condition for which the predicted comfort feedback satisfies a condition; and assigning the maximum value and the minimum value as the one or more thresholds.
 14. The method of claim 8, wherein the one or more thresholds comprises one or more time-varying values for a plurality of time steps in an optimization period.
 15. Non-transitory computer-readable media storing program instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising; obtaining comfort feedback provided by one or more occupants of a building while the one or more occupants are exposed to a first set of environmental conditions of the building; generating, based on the comfort feedback, one or more thresholds defining a range of values for an environmental condition of the building within which the one or more occupants are predicted to be comfortable; executing a predictive control process subject to one or more constraints based on the one or more thresholds to generate setpoints for building equipment; and operating the building equipment to drive the environmental condition of the building toward the setpoints.
 16. The non-transitory computer-readable media of claim 15, wherein the comfort feedback comprises setpoint adjustments provided by the one or more occupants during a first time period; and the one or more occupants are predicted to be comfortable in response to a prediction that the setpoint adjustments will satisfy a condition during a second time period.
 17. The non-transitory computer-readable media of claim 15, wherein the comfort feedback comprises comfort votes provided by the one or more occupants via a mobile device during a first time period; and the one or more occupants are predicted to be comfortable in response to a prediction that the comfort votes will satisfy a condition during a second time period.
 18. The non-transitory computer-readable media of claim 15, the operations further comprising predicting whether the one or more occupants will be comfortable at a value of the environmental condition using a neural network model trained with the comfort feedback and corresponding values of the first set of environmental conditions of the building.
 19. The non-transitory computer-readable media of claim 15, wherein generating the one or more thresholds comprises using a neural network comprising an input neuron for a value for the environmental condition and configured to output a predicted setpoint change.
 20. The non-transitory computer-readable media of claim 19, wherein the neural network is updated over time using additional comfort feedback.
 21. The non-transitory computer-readable media of claim 19, wherein generating the one or more thresholds comprises: iteratively applying a plurality of values for the environmental condition at the input neuron to obtain a plurality of predicted setpoint changes associated with the plurality of values for the environmental condition; determining, from the plurality of values for the environmental condition and the plurality of predicted setpoint changes: a maximum value for the environmental condition for which the predicted setpoint change is zero; and a minimum value for the environmental condition for which the predicted setpoint change is zero; and using the maximum value and the minimum value to define the one or more thresholds.
 22. The non-transitory computer-readable media of claim 21, wherein the values for the environmental condition are zone temperature values and wherein the predicted setpoint changes are predicted temperature setpoint changes. 